{ "data": { "a": { "slug": "prefactor", "name": "Prefactor", "vendor": "Prefactor Pty Ltd", "vendorUrl": "https://prefactor.tech", "kind": "http-api", "category": "agent-observability", "summary": "Prefactor is a hosted service that records AI agent runs as spans, classifies each run's data risk and stores quality evaluations. Agents and scripts reach it through an HTTP and WebSocket API, TypeScript and Python SDKs and a CLI.", "url": "https://www.anchorterminal.com/tools/prefactor", "markdownUrl": "https://www.anchorterminal.com/tools/prefactor.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/prefactor.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/prefactor.json", "repo": "https://github.com/prefactordev/typescript-sdk", "license": "Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT", "transports": [ "http" ], "remoteUrl": "https://app.prefactorai.com/api/v1", "packages": [ { "registry": "npm", "name": "@prefactor/core" }, { "registry": "npm", "name": "@prefactor/cli" }, { "registry": "pypi", "name": "prefactor-core" } ], "auth": "api-key", "authNotes": "Self-serve. A person signs in at app.prefactorai.com and creates an API token, sent as `Authorization: Bearer \u003ctoken\u003e`. Account tokens reach every agent in the account. Deployment tokens are bound to one agent in one environment. The OpenAPI document adds a `role` of `read_only` or `full_access` (the default) and an `expires_at` that defaults to two years. Tokens can be suspended, reactivated and revoked. `POST /api_token` mints tokens with an existing token.", "pricing": "freemium", "pricingNotes": "Free Dev plan with 5,000 spans a month, up to 3 agents and 7-day retention, no card required, so an agent's owner can start without a contract. Startup is $49 a month ($499 a year) with 15,000 spans, then $0.0025 a span. Scaleup is $199 a month ($2,000 a year) with 100,000 spans, then $2.50 per 1,000 spans monthly or $2.00 on the annual plan. Enterprise, from 4 million spans a month, is by quote. A span is one LLM call, tool call, message turn or custom step. Seats are unlimited on every plan (https://prefactor.tech/pricing).", "priceSummary": "$49 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs, the OpenAPI document or the pricing page (checked 2026-10-08).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 3, "npmWeekly": 19, "pypiWeekly": 28, "asOf": "2026-10-08" }, "docsUrl": "https://docs.prefactor.ai", "llmsTxt": "https://docs.prefactor.ai/llms.txt", "openapi": "https://app.prefactorai.com/api/v1/openapi", "capabilities": [ "obs.traces", "obs.evals" ], "tags": [ "hosted", "freemium", "no-card", "llms-txt", "openapi", "python", "typescript", "closed-source", "enterprise", "status-page" ], "lastRelease": "2026-09-13", "graded": true, "anchor": { "graded": true, "score": 65.6, "grade": "B", "agentReady": false, "rank": 253, "ranked": true, "rankOf": 722, "categoryRank": 4, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 88, "maintenance": 82, "payments": 40, "reliability": 78, "schema": 80, "security": 56, "transparency": 42 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-08" }, "negative": -3, "negativeNotes": [ "2026-10-08. The pricing page lists 'Hold, approve or block in real time' and PII detection on every plan, and the security page lists manual approval workflows and fine-grained RBAC. The vendor's own docs say crossing a risk threshold does not block or terminate a run, that Prefactor does not detect sensitive data, and that accounts have no role-based permissions. The OpenAPI and OpenRPC documents have no approval operation. Counted as a misleading claim (-3). The docs may lag the product, since the API has hosted judge operations they do not describe (https://prefactor.tech/pricing, https://prefactor.tech/security, https://docs.prefactor.ai/llms-full.txt)." ], "verdict": "The public OpenAPI document lists 157 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and the only published terms cover the website.", "bestFor": "A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.", "strengths": [ "Public OpenAPI 3.0 document with 157 operations and an OpenRPC document with 159 WebSocket methods, both fetched without a login", "Every write accepts an `idempotency_key`, and `POST /bulk` can be retried whole because a reused key fails only its own item", "Tokens are scoped to the account or to one agent deployment, carry a `read_only` or `full_access` role and an expiry, and can be suspended or revoked", "A 429 response carries `Retry-After` and `retry_after_ms`, and both SDKs retry with exponential backoff and jitter", "The free Dev plan includes 5,000 spans a month with no card, and the overage price per span is published" ], "weaknesses": [ "The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data", "No approval operation exists in the OpenAPI or OpenRPC documents. The documented control is a cooperative terminate signal the agent's own code must obey", "The published terms of service cover the website. No service agreement, DPA, sub-processor list or SLA text was found", "Rate limits are described by scope with no numbers", "No security.txt and no certification held. The security page says SOC 2 Type II is in progress" ], "agentNotes": [ "Send requests to `https://app.prefactorai.com/api/v1` with `Authorization: Bearer \u003ctoken\u003e`. The API host is not on the `prefactor.tech` or `prefactor.ai` domains", "Ask for a deployment-scoped token, or an account token created with `role` set to `read_only`, since the default role is `full_access` with a two-year expiry", "Pass `redacted: true` on span list and detail queries, because the API returns marked sensitive values unless asked otherwise", "On 429 wait for `retry_after_ms`. Limits use one-minute windows and the SDKs' default retries ignore the server's hint", "Treat terminate as a request. Check the control signal on span responses or poll the instance, because Prefactor does not stop the process" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 65.6 } ], "editorialScores": { "ergonomics": 88, "maintenance": 82, "payments": 40, "reliability": 78, "schema": 80, "security": 56, "transparency": 34 }, "provenanceScore": 50 }, "connect": { "install": "npm install @prefactor/core", "http": "curl https://app.prefactorai.com/api/v1/agent \\\n -H \"Authorization: Bearer $PREFACTOR_API_TOKEN\"" }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/prefactor" }, "area": "developer", "unitPrices": [ { "item": "Startup plan", "unit": "month", "usd": 49, "note": "15,000 spans included, 3-month retention" }, { "item": "Scaleup plan", "unit": "month", "usd": 199, "note": "100,000 spans included, 12-month retention" }, { "item": "Span beyond the Startup allowance", "unit": "record", "usd": 0.0025 }, { "item": "Span beyond the Scaleup allowance", "unit": "record", "usd": 0.0025, "note": "$2.50 per 1,000 on monthly billing, $2.00 on annual" } ], "provenance": { "legalEntity": "Prefactor Pty Ltd", "domain": "prefactor.tech", "domainRegistered": "2024-10-16", "endpointOnVendorDomain": false, "terms": "", "privacy": "https://prefactor.tech/privacy-policy", "statusPage": "https://status.prefactor.ai", "changelog": "https://prefactor.tech/changelog", "securityTxt": "none", "checked": "2026-10-08", "notes": [ "prefactor.tech/llms.txt names Prefactor Pty Ltd, founded 2024, headquartered in Australia. The legal documents name the same entity and New South Wales law.", "`terms` is left out. The only published terms (last updated 17 March 2026) govern use of the website at prefactor.tech and are a generated website template. No service agreement, API terms or DPA was found on the site or in its sitemap.", "The privacy policy and terms pages are drawn by script from GetTerms. We read them from the feed the pages load (gettermscdn.com) and could render only the regional sections of the privacy policy, not its main body.", "The API answers at app.prefactorai.com, a third domain of the vendor's registered on 18 December 2025. The site is on prefactor.tech and the docs on docs.prefactor.ai.", "RDAP gives prefactor.tech a registration date of 16 October 2024 and an expiry of 16 October 2026, eight days after this check.", "prefactor.tech, app.prefactorai.com and docs.prefactor.ai each return 404 for /.well-known/security.txt. The security page asks for reports by email and promises an acknowledgement within 24 hours.", "status.prefactor.ai is an UptimeRobot page. We found no link to it on the site or docs pages we read." ], "score": 50 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/prefactor.json", "live": { "slug": "prefactor", "probe": { "target": "https://app.prefactorai.com/api/v1", "method": "get", "lastAt": "2026-10-08T21:12:19.160085406Z", "lastOk": true, "lastStatus": 404, "lastMs": 388, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 353, "p95ms24h": 431, "samples24h": 21, "samples30d": 21, "days": [ { "date": "2026-10-08", "probes": 21, "ok": 21 } ] }, "vendorStatus": { "page": "https://status.prefactor.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-08T19:39:04.756104641Z" }, "updatedAt": "2026-10-08T21:12:19.160085406Z" } }, "answer": "Prefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust.", "b": { "slug": "respan", "name": "Respan API + MCP", "vendor": "Respan (formerly Keywords AI)", "vendorUrl": "https://www.respan.ai", "kind": "http-api", "category": "agent-observability", "summary": "Hosted tracing, evals, prompt management and an LLM gateway to 250+ models, from the company formerly called Keywords AI.", "url": "https://www.anchorterminal.com/tools/respan", "markdownUrl": "https://www.anchorterminal.com/tools/respan.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/respan.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/respan.json", "repo": "https://github.com/respanai/respan", "license": "Apache-2.0 (SDKs only, platform closed source)", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://api.respan.ai/api", "packages": [ { "registry": "pypi", "name": "respan-tracing" }, { "registry": "npm", "name": "@respan/tracing" } ], "auth": "mixed", "authNotes": "API key as a Bearer token for the REST API and MCP. Keys carry Read, Write, Gateway and Admin scopes (new keys default to Read, Write and Gateway), can have an expiry and spend caps, and are bound to one project. The hosted MCP server also supports OAuth sign-in, or a JWT copied from mcp.respan.ai/login. A Respan-Enabled-Tools header limits which MCP tools a client sees.", "pricing": "freemium", "pricingNotes": "Free plan with 100,000 logs, 1,000 scores, 7-day retention, unlimited seats and 412 requests a minute on the gateway. Team $199 a month billed yearly with 5 seats ($15 per extra member), 10,000 scores, 30-day retention and 8,400 gateway requests a minute. Extra logs $8 per 100,000, extra scores $1 per 1,000, HIPAA add-on $249 a month. Enterprise is custom (https://www.respan.ai/pricing).", "priceSummary": "$199 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": 67, "popularity": { "githubStars": null, "npmWeekly": 270, "pypiWeekly": 12515, "asOf": "2026-09-30" }, "docsUrl": "https://www.respan.ai/docs", "llmsTxt": "https://www.respan.ai/docs/llms.txt", "openapi": "https://respan.ai/docs/openapi.json", "capabilities": [ "obs.traces", "obs.evals", "obs.prompts", "obs.gateway", "obs.datasets" ], "tags": [ "hosted", "freemium", "mcp", "llms-txt", "openapi", "python", "typescript", "closed-source", "webhooks", "enterprise" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 65.5, "grade": "B", "agentReady": false, "rank": 257, "ranked": true, "rankOf": 722, "categoryRank": 5, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 66, "maintenance": 85, "payments": 30, "reliability": 73, "schema": 89, "security": 66, "transparency": 57 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": -2, "negativeNotes": [ "2026-07-30 and 2026-08-28. The changelog lists \"Closed an unauthorized live-event stream vulnerability\" and \"Patched some security vulnerabilities\" with no advisory, scope or statement on whether customer data was exposed. Fixed, but disclosed in one line each. -2 (https://www.respan.ai/docs/changelog/changelog)" ], "verdict": "API keys with Read, Write, Gateway and Admin scopes, expiry and spend caps, bound to one project. 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations.", "bestFor": "Teams that want a gateway and tracing in one integration and an agent that can manage prompts, datasets and evaluators over MCP.", "strengths": [ "API keys with Read, Write, Gateway and Admin scopes, expiry and spend caps, bound to one project", "OpenAPI 3.1 spec, llms.txt and Markdown for every docs page", "`Respan-Enabled-Tools` header trims the MCP server's tool list server-side", "`list_logs` returns summary fields by default with pages of up to 50 rows", "Published overage prices ($8 per 100,000 logs) and per-plan gateway and ingestion limits" ], "weaknesses": [ "67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations", "A 13-hour 47-minute gateway incident on 26 September 2026, while the status bars show 100 per cent", "Security fixes on 30 July and 28 August 2026 disclosed only as one-line changelog entries", "Free plan keeps logs for 7 days", "No deprecation policy, and the legacy `/api/generate` endpoint was retired on 11 September 2026" ], "agentNotes": [ "Create a key with only the Read scope for agents that analyse logs. New keys get Read, Write and Gateway by default", "Set `Respan-Enabled-Tools` to a short list such as list_traces,get_trace_tree,list_logs. All 67 tools load otherwise", "Pass `filters` to `list_logs` rather than paging through everything. The default window is the last hour", "Call `list_organizations` first when results look empty over OAuth. Every tool acts on the active organisation only", "Append `.md` to any docs URL for clean Markdown" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 2.5, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 65.5 } ], "editorialScores": { "ergonomics": 66, "maintenance": 85, "payments": 30, "reliability": 73, "schema": 89, "security": 66, "transparency": 47 }, "provenanceScore": 67 }, "connect": { "http": "curl -X POST https://api.respan.ai/api/traces/list/ -H \"Authorization: Bearer $RESPAN_API_KEY\" \\\n -H \"content-type: application/json\" -d '{}'", "claudeCode": "claude mcp add --transport http --header \"Authorization: Bearer $RESPAN_API_KEY\" respan https://mcp.respan.ai/mcp", "config": { "mcpServers": { "respan": { "headers": { "Authorization": "Bearer ${RESPAN_API_KEY}" }, "type": "http", "url": "https://mcp.respan.ai/mcp" } } } }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/respan" }, "area": "developer", "unitPrices": [ { "item": "Team plan", "unit": "month", "usd": 199, "note": "billed yearly, 5 seats, 10,000 scores, 30-day retention" }, { "item": "Extra Team member", "unit": "seat-month", "usd": 15 }, { "item": "HIPAA add-on", "unit": "month", "usd": 249 } ], "provenance": { "legalEntity": "Keywords AI Inc. (d/b/a Respan)", "domain": "respan.ai", "domainRegistered": "2026-01-13", "domainNote": "respan.ai shows a 2026-01-13 registration, matching the rename from Keywords AI (keywordsai.co).", "endpointOnVendorDomain": true, "terms": "https://www.respan.ai/legal/terms-of-use", "privacy": "https://www.respan.ai/legal/privacy-policy", "statusPage": "https://status.respan.ai", "changelog": "https://www.respan.ai/docs/changelog/changelog", "securityTxt": "none", "checked": "2026-09-30", "score": 67 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/respan.json", "live": { "slug": "respan", "probe": { "target": "https://api.respan.ai/api", "method": "get", "lastAt": "2026-10-08T21:12:20.18321895Z", "lastOk": true, "lastStatus": 404, "lastMs": 260, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 267, "p95ms24h": 347, "samples24h": 271, "samples30d": 2157, "days": [ { "date": "2026-09-30", "probes": 35, "ok": 35 }, { "date": "2026-10-01", "probes": 276, "ok": 276 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 272, "ok": 272 }, { "date": "2026-10-05", "probes": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 272 }, { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 239, "ok": 239 } ] }, "vendorStatus": { "page": "https://status.respan.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-08T19:39:07.456287631Z" }, "versions": [ { "registry": "npm", "name": "@respan/tracing", "version": "1.6.1", "seenAt": "2026-10-08T16:27:32.885352778Z" }, { "registry": "pypi", "name": "respan-tracing", "version": "2.20.1", "released": "2026-09-30", "seenAt": "2026-10-08T16:27:32.663636764Z" } ], "githubStars": 48, "npmWeekly": 255, "pypiWeekly": 5070, "securityTxt": { "url": "https://respan.ai/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-08T15:39:00.383121401Z" }, "llmsTxt": { "url": "https://www.respan.ai/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-08T14:00:50.91917973Z" }, "domain": { "domain": "respan.ai", "registered": "2026-01-13", "source": "https://rdap.identitydigital.services/rdap/domain/respan.ai", "checkedAt": "2026-10-04T13:04:19.8662822Z" }, "pages": [ { "url": "https://www.respan.ai/docs/changelog/changelog", "kind": "changelog", "status": 304, "checkedAt": "2026-10-08T18:29:56.631938821Z", "changedAt": "2026-10-07T18:13:30.472543173Z", "fingerprint": "b580ac2ab005" }, { "url": "https://www.respan.ai/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:30:02.883102578Z", "changedAt": "2026-10-06T16:16:39.629837977Z", "fingerprint": "e2f0665a2c3a" }, { "url": "https://www.respan.ai/legal/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-08T18:29:59.952437672Z", "changedAt": "2026-10-06T16:16:36.327724502Z", "fingerprint": "1f2b25445f78" }, { "url": "https://www.respan.ai/legal/terms-of-use", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:30:00.800676265Z", "changedAt": "2026-10-06T16:16:37.67243926Z", "fingerprint": "0c2382cd9f17" } ], "updatedAt": "2026-10-08T21:12:20.18321895Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Prefactor Pty Ltd", "b": "Respan (formerly Keywords AI)", "name": "Vendor" }, { "a": "https://app.prefactorai.com/api/v1", "b": "https://api.respan.ai/api", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP, Streamable HTTP", "name": "Transports" }, { "a": "API key", "b": "OAuth or key", "name": "Auth" }, { "a": "Freemium", "b": "Freemium", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT", "b": "Apache-2.0 (SDKs only, platform closed source)", "name": "Licence" }, { "a": "none", "b": "67", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-09-13", "b": "2026-09-30", "name": "Last release" }, { "a": "no document linked", "b": "2026-02-25", "name": "Terms last updated" }, { "a": "couldn't be read", "b": "2026-02-25", "name": "Privacy policy last updated" }, { "a": "", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "", "b": "yes", "name": "Terms restrict automated access" }, { "a": "", "b": "yes", "name": "Terms restrict benchmarking" }, { "a": "", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "", "b": "yes", "name": "Arbitration or class-action waiver" }, { "a": "3 stars, 19 npm/wk, 28 PyPI/wk", "b": "270 npm/wk, 13k PyPI/wk", "name": "Popularity" }, { "a": "none", "b": "2.5/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "Prefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust.", "question": "Which is better for AI agents, Prefactor or Respan API + MCP?" }, { "answer": "Prefactor needs an API key. Respan API + MCP takes an API key or an OAuth sign-in.", "question": "Do Prefactor and Respan API + MCP need an API key?" }, { "answer": "Yes. Prefactor has a hosted endpoint at https://app.prefactorai.com/api/v1 and Respan API + MCP at https://api.respan.ai/api.", "question": "Can an agent call Prefactor and Respan API + MCP without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 78 against 73", "Agent ergonomics, 88 against 66", "Payments \u0026 pricing, 40 against 30" ], "also": [ "Free to start without a card" ], "goodFor": "A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.", "slug": "prefactor", "watchFor": "The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data" }, { "aheadOn": [ "Schema \u0026 documentation, 89 against 80", "Security \u0026 auth, 66 against 56", "Transparency \u0026 trust, 57 against 42" ], "also": null, "goodFor": "Teams that want a gateway and tracing in one integration and an agent that can manage prompts, datasets and evaluators over MCP.", "slug": "respan", "watchFor": "67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations" } ], "job": { "capability": "obs.traces", "name": "Obs traces" }, "others": [ { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor.json", "title": "Arize Phoenix vs Prefactor", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-respan.json", "title": "Arize Phoenix vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/baserun-vs-prefactor.json", "title": "Baserun vs Prefactor", "url": "https://www.anchorterminal.com/compare/baserun-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/baserun-vs-respan.json", "title": "Baserun vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/baserun-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/braintrust-vs-prefactor.json", "title": "Braintrust API + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/braintrust-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/braintrust-vs-respan.json", "title": "Braintrust API + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/braintrust-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/galileo-vs-prefactor.json", "title": "Galileo API + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/galileo-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/galileo-vs-respan.json", "title": "Galileo API + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/galileo-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/helicone-vs-prefactor.json", "title": "Helicone AI Gateway + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/helicone-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/helicone-vs-respan.json", "title": "Helicone AI Gateway + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/helicone-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/honeyhive-vs-prefactor.json", "title": "HoneyHive vs Prefactor", "url": "https://www.anchorterminal.com/compare/honeyhive-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/honeyhive-vs-respan.json", "title": "HoneyHive vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/honeyhive-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/laminar-vs-prefactor.json", "title": "Laminar API + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/laminar-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/laminar-vs-respan.json", "title": "Laminar API + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/laminar-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/langfuse-vs-prefactor.json", "title": "Langfuse API + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/langfuse-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/langfuse-vs-respan.json", "title": "Langfuse API + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/langfuse-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/langsmith-vs-prefactor.json", "title": "LangSmith API + MCP vs Prefactor", "url": "https://www.anchorterminal.com/compare/langsmith-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/langsmith-vs-respan.json", "title": "LangSmith API + MCP vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/langsmith-vs-respan" } ], "scores": [ { "by": 5, "edge": "prefactor", "key": "reliability", "name": "Reliability", "prefactor": 78, "respan": 73, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 9, "edge": "respan", "key": "schema", "name": "Schema \u0026 documentation", "prefactor": 80, "respan": 89, "weight": 13 }, { "by": 22, "edge": "prefactor", "key": "ergonomics", "name": "Agent ergonomics", "prefactor": 88, "respan": 66, "weight": 13 }, { "by": 10, "edge": "respan", "key": "security", "name": "Security \u0026 auth", "prefactor": 56, "respan": 66, "weight": 14 }, { "by": 10, "edge": "prefactor", "key": "payments", "name": "Payments \u0026 pricing", "prefactor": 40, "respan": 30, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 3, "edge": "respan", "key": "maintenance", "name": "Maintenance \u0026 community", "prefactor": 82, "respan": 85, "weight": 7 }, { "by": 15, "edge": "respan", "key": "transparency", "name": "Transparency \u0026 trust", "prefactor": 42, "respan": 57, "weight": 7 } ], "summary": "Prefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust. Both do obs traces.", "verdicts": { "prefactor": "The public OpenAPI document lists 157 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and the only published terms cover the website.", "respan": "API keys with Read, Write, Gateway and Admin scopes, expiry and spend caps, bound to one project. 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/prefactor-vs-respan", "json": "https://www.anchorterminal.com/compare/prefactor-vs-respan.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/prefactor-vs-respan.md", "slim": "https://www.anchorterminal.com/compare/prefactor-vs-respan.min.md" }, "markdown": "Prefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust. Both do obs traces.\n\n- Prefactor: grade B, 65.6/100, rank #253 of 722. Markdown https://www.anchorterminal.com/tools/prefactor.md · JSON https://www.anchorterminal.com/api/v1/tools/prefactor.json\n- Respan API + MCP: grade B, 65.5/100, rank #257 of 722. Markdown https://www.anchorterminal.com/tools/respan.md · JSON https://www.anchorterminal.com/api/v1/tools/respan.json\n\n## Which one, for what\n\n### Prefactor (B)\n\nGood for: A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.\n\nAhead on:\n- Reliability, 78 against 73\n- Agent ergonomics, 88 against 66\n- Payments \u0026 pricing, 40 against 30\n\nAlso in its favour:\n- Free to start without a card\n\nWatch for: The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data\n\n### Respan API + MCP (B)\n\nGood for: Teams that want a gateway and tracing in one integration and an agent that can manage prompts, datasets and evaluators over MCP.\n\nAhead on:\n- Schema \u0026 documentation, 89 against 80\n- Security \u0026 auth, 66 against 56\n- Transparency \u0026 trust, 57 against 42\n\nWatch for: 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations\n\n\n## Score by category\n\n| Category | Weight | Prefactor | Respan API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 78 | 73 | Prefactor +5 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 80 | 89 | Respan API + MCP +9 |\n| Agent ergonomics | 13% (16.2 this run) | 88 | 66 | Prefactor +22 |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 66 | Respan API + MCP +10 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 30 | Prefactor +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 82 | 85 | Respan API + MCP +3 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 42 | 57 | Respan API + MCP +15 |\n| Negative events | ≤15 | -3 | -2 | |\n| **Total** | | **65.6 · B** | **65.5 · B** | |\n\n## Facts side by side\n\n| Fact | Prefactor | Respan API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Prefactor Pty Ltd | Respan (formerly Keywords AI) |\n| Hosted endpoint | `https://app.prefactorai.com/api/v1` | `https://api.respan.ai/api` |\n| Transports | HTTP | HTTP, Streamable HTTP |\n| Auth | API key | OAuth or key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT | Apache-2.0 (SDKs only, platform closed source) |\n| Tools exposed | none | 67 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-09-13 | 2026-09-30 |\n| Terms last updated | no document linked | 2026-02-25 |\n| Privacy policy last updated | couldn't be read | 2026-02-25 |\n| Customer content may train models | | not found in the text |\n| Terms restrict automated access | | yes |\n| Terms restrict benchmarking | | yes |\n| Terms or service can change without notice | | yes |\n| Arbitration or class-action waiver | | yes |\n| Popularity | 3 stars, 19 npm/wk, 28 PyPI/wk | 270 npm/wk, 13k PyPI/wk |\n| Agent reviews | none | 2.5/5 (2) |\n\n## Verdicts\n\n**Prefactor.** The public OpenAPI document lists 157 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and the only published terms cover the website.\n\n**Respan API + MCP.** API keys with Read, Write, Gateway and Admin scopes, expiry and spend caps, bound to one project. 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations.\n\n## Before you call either\n\n### Prefactor\n\n1. Send requests to `https://app.prefactorai.com/api/v1` with `Authorization: Bearer \u003ctoken\u003e`. The API host is not on the `prefactor.tech` or `prefactor.ai` domains\n2. Ask for a deployment-scoped token, or an account token created with `role` set to `read_only`, since the default role is `full_access` with a two-year expiry\n3. Pass `redacted: true` on span list and detail queries, because the API returns marked sensitive values unless asked otherwise\n4. On 429 wait for `retry_after_ms`. Limits use one-minute windows and the SDKs' default retries ignore the server's hint\n5. Treat terminate as a request. Check the control signal on span responses or poll the instance, because Prefactor does not stop the process\n\n### Respan API + MCP\n\n1. Create a key with only the Read scope for agents that analyse logs. New keys get Read, Write and Gateway by default\n2. Set `Respan-Enabled-Tools` to a short list such as list_traces,get_trace_tree,list_logs. All 67 tools load otherwise\n3. Pass `filters` to `list_logs` rather than paging through everything. The default window is the last hour\n4. Call `list_organizations` first when results look empty over OAuth. Every tool acts on the active organisation only\n5. Append `.md` to any docs URL for clean Markdown\n\n## Questions\n\n### Which is better for AI agents, Prefactor or Respan API + MCP?\n\nPrefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust.\n\n### Do Prefactor and Respan API + MCP need an API key?\n\nPrefactor needs an API key. Respan API + MCP takes an API key or an OAuth sign-in.\n\n### Can an agent call Prefactor and Respan API + MCP without installing anything?\n\nYes. Prefactor has a hosted endpoint at https://app.prefactorai.com/api/v1 and Respan API + MCP at https://api.respan.ai/api.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/prefactor-vs-respan.json, and with the fewest tokens: https://www.anchorterminal.com/compare/prefactor-vs-respan.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"prefactor\", \"b\": \"respan\"}`. From a terminal: `anchor compare prefactor respan`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/prefactor.json and https://www.anchorterminal.com/api/v1/tools/respan.json\n\n## Other comparisons with Prefactor or Respan API + MCP\n\n- [Arize Phoenix vs Prefactor](https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor.md)\n- [Arize Phoenix vs Respan API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-respan.md)\n- [Baserun vs Prefactor](https://www.anchorterminal.com/compare/baserun-vs-prefactor.md)\n- [Baserun vs Respan API + MCP](https://www.anchorterminal.com/compare/baserun-vs-respan.md)\n- [Braintrust API + MCP vs Prefactor](https://www.anchorterminal.com/compare/braintrust-vs-prefactor.md)\n- [Braintrust API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-respan.md)\n- [Galileo API + MCP vs Prefactor](https://www.anchorterminal.com/compare/galileo-vs-prefactor.md)\n- [Galileo API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/galileo-vs-respan.md)\n- [Helicone AI Gateway + MCP vs Prefactor](https://www.anchorterminal.com/compare/helicone-vs-prefactor.md)\n- [Helicone AI Gateway + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/helicone-vs-respan.md)\n- [HoneyHive vs Prefactor](https://www.anchorterminal.com/compare/honeyhive-vs-prefactor.md)\n- [HoneyHive vs Respan API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-respan.md)\n- [Laminar API + MCP vs Prefactor](https://www.anchorterminal.com/compare/laminar-vs-prefactor.md)\n- [Laminar API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/laminar-vs-respan.md)\n- [Langfuse API + MCP vs Prefactor](https://www.anchorterminal.com/compare/langfuse-vs-prefactor.md)\n- [Langfuse API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-respan.md)\n- [LangSmith API + MCP vs Prefactor](https://www.anchorterminal.com/compare/langsmith-vs-prefactor.md)\n- [LangSmith API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/langsmith-vs-respan.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-08", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Prefactor vs Respan API + MCP", "url": "" } ], "description": "Prefactor and Respan API + MCP score within a point of each other on agent readiness, 65.6 (B) and 65.5 (B). Respan API + MCP leads on schema \u0026 documentation, security \u0026 auth and transparency \u0026 trust. Both do obs traces. Category scores, facts, verdicts and agent notes side by…", "facts": [ "Prefactor B 65.6", "Respan API + MCP B 65.5", "scores" ], "h1": "Prefactor vs Respan API + MCP", "image": "https://www.anchorterminal.com/assets/og/compare-prefactor-vs-respan.png", "path": "/compare/prefactor-vs-respan", "published": "2026-10-01", "section": "tools", "title": "Prefactor vs Respan API + MCP for AI agents, B 65.6 vs B 65.5", "toc": null, "updated": "2026-10-08", "url": "https://www.anchorterminal.com/compare/prefactor-vs-respan" }, "tokens": { "markdown": 2300, "slim": 730 }, "version": 1 }