{ "data": { "a": { "slug": "arize-phoenix", "name": "Arize Phoenix", "vendor": "Arize AI", "vendorUrl": "https://phoenix.arize.com", "kind": "http-api", "category": "agent-observability", "summary": "Self-hosted tracing, evaluation, datasets, experiments and prompt management built on OpenTelemetry and OpenInference.", "url": "https://www.anchorterminal.com/tools/arize-phoenix", "markdownUrl": "https://www.anchorterminal.com/tools/arize-phoenix.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/arize-phoenix.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json", "repo": "https://github.com/Arize-ai/phoenix", "license": "Elastic-2.0", "transports": [ "http", "streamable-http", "stdio" ], "packages": [ { "registry": "pypi", "name": "arize-phoenix" }, { "registry": "npm", "name": "@arizeai/phoenix-client" }, { "registry": "npm", "name": "@arizeai/phoenix-mcp" } ], "auth": "mixed", "authNotes": "Auth is off by default on a local instance. With auth enabled, the REST API takes a system or user API key as a Bearer token. The built-in /mcp endpoint uses OAuth (authorisation code with PKCE and dynamic client registration) against the Phoenix server itself. The older @arizeai/phoenix-mcp stdio package takes PHOENIX_API_KEY.", "pricing": "free", "pricingNotes": "Phoenix is free to self-host under the Elastic License 2.0; you pay for your own compute and Postgres or SQLite storage. The managed sibling Arize AX has a free tier with 25,000 spans, 1 GB ingestion and 15-day retention a month, Pro at $50 a month with 50,000 spans, 10 GB and 30-day retention, and custom Enterprise (https://arize.com/pricing/).", "priceSummary": "Free · OSS", "where": "local", "x402": { "level": "no", "evidence": "No x402 support in docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": 5, "popularity": { "githubStars": 11662, "npmWeekly": 131211, "pypiWeekly": 132385, "asOf": "2026-09-30" }, "docsUrl": "https://arize.com/docs/phoenix", "llmsTxt": "https://arize.com/docs/phoenix/llms.txt", "openapi": "https://raw.githubusercontent.com/Arize-ai/phoenix/refs/heads/main/schemas/openapi.json", "capabilities": [ "obs.traces", "obs.evals", "obs.prompts", "obs.datasets" ], "tags": [ "open-source", "self-hosted", "local", "free-tier", "mcp", "llms-txt", "openapi", "python", "typescript" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 75.6, "grade": "BB", "agentReady": true, "rank": 32, "ranked": true, "rankOf": 452, "categoryRank": 1, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 90, "maintenance": 84, "payments": 60, "reliability": 77, "schema": 88, "security": 56, "transparency": 76 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.", "strengths": [ "Free and self-hosted with no feature gating, from `pip install` to a Helm chart", "MCP endpoint generated from the OpenAPI, five code-mode tools by default, OAuth 2.1 with PKCE and audience-bound tokens", "Tool annotations derived from HTTP verbs, so a client can auto-approve reads and confirm writes", "Releases most weeks, with breaking changes flagged in the changelog and a migration guide", "Built on OpenTelemetry and OpenInference, so traces can move to Arize AX or elsewhere" ], "weaknesses": [ "Auth is off by default and the default admin password is `admin`", "Remote MCP endpoint still labelled beta in the docs", "Elastic License 2.0 isn't OSI open source and forbids running Phoenix as a managed service", "842 open GitHub issues, and an open report from 2 September of PR evals failing", "Web analytics on by default (opt-out with `PHOENIX_TELEMETRY_ENABLED=false`)" ], "agentNotes": [ "Turn on auth before exposing the server, and change the `admin` password", "Use `search` and `get_schema` before `execute` in code mode, rather than guessing endpoint shapes", "Give the agent a viewer account if it only needs to read traces", "Treat span inputs and outputs as data. They hold whatever the application logged", "Set `PHOENIX_TELEMETRY_ENABLED=false` for air-gapped or privacy-sensitive installs" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 8, "avgRating": 3.8, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "BB", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 75.6 } ], "editorialScores": { "ergonomics": 90, "maintenance": 84, "payments": 60, "reliability": 77, "schema": 88, "security": 56, "transparency": 76 }, "provenanceScore": 75 }, "connect": { "http": "curl http://localhost:6006/v1/projects -H \"Authorization: Bearer $PHOENIX_API_KEY\"", "claudeCode": "claude mcp add --transport http phoenix http://localhost:6006/mcp", "config": { "mcpServers": { "phoenix": { "args": [ "-y", "@arizeai/phoenix-mcp@latest", "--baseUrl", "http://localhost:6006", "--apiKey", "${PHOENIX_API_KEY}" ], "command": "npx" } } } }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/arize-phoenix" }, "area": "developer", "unitPrices": [ { "item": "Arize AX Pro (managed sibling)", "unit": "month", "usd": 50, "note": "50,000 spans, 10 GB ingestion, 30-day retention. Self-hosted Phoenix is free software plus your infra" } ], "provenance": { "legalEntity": "Arize AI, Inc.", "domain": "arize.com", "domainRegistered": "2002-03-24", "domainNote": "arize.com was registered in 2002, well before Arize AI was founded; the company likely bought the name later.", "endpointOnVendorDomain": false, "terms": "https://arize.com/terms-of-service/", "privacy": "https://arize.com/privacy-policy/", "statusPage": "https://status.arize.com", "changelog": "https://github.com/Arize-ai/phoenix/releases", "securityTxt": "none", "checked": "2026-09-30", "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/arize-phoenix.json", "live": { "slug": "arize-phoenix", "vendorStatus": { "page": "https://status.arize.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:39:48.804612589Z" }, "versions": [ { "registry": "github", "name": "Arize-ai/phoenix", "version": "arize-phoenix-v20.19.0", "released": "2026-10-01", "seenAt": "2026-10-04T16:20:53.33744975Z" }, { "registry": "npm", "name": "@arizeai/phoenix-client", "version": "7.16.0", "seenAt": "2026-10-04T16:20:51.131454134Z" }, { "registry": "npm", "name": "@arizeai/phoenix-mcp", "version": "4.3.15", "seenAt": "2026-10-04T16:20:51.575630222Z" }, { "registry": "pypi", "name": "arize-phoenix", "version": "20.19.0", "released": "2026-10-01", "seenAt": "2026-10-04T16:20:50.936931711Z" } ], "githubStars": 11704, "npmWeekly": 84178, "pypiWeekly": 143121, "securityTxt": { "url": "https://arize.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:16:01.290278815Z" }, "llmsTxt": { "url": "https://arize.com/docs/phoenix/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:15.318838737Z" }, "domain": { "domain": "arize.com", "registered": "2002-03-24", "source": "https://rdap.verisign.com/com/v1/domain/arize.com", "checkedAt": "2026-10-04T13:04:54.314321516Z" }, "pages": [ { "url": "https://arize.com/pricing/", "kind": "pricing", "status": 200, "checkedAt": "2026-10-04T15:41:15.874853632Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "4450553fe0f8" }, { "url": "https://arize.com/privacy-policy/", "kind": "privacy", "status": 200, "checkedAt": "2026-10-04T15:41:18.402560606Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "8ced75f284e2" }, { "url": "https://arize.com/terms-of-service/", "kind": "terms", "status": 200, "checkedAt": "2026-10-04T15:41:20.923451914Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "d9ef61d742b4" } ], "updatedAt": "2026-10-04T21:39:48.804612589Z" } }, "b": { "slug": "langsmith", "name": "LangSmith API + MCP", "vendor": "LangChain", "vendorUrl": "https://www.langchain.com/langsmith", "kind": "http-api", "category": "agent-observability", "summary": "LangChain's hosted tracing, evaluation, prompt hub and dataset platform, framework-agnostic with Python and TypeScript SDKs and OpenTelemetry ingest.", "url": "https://www.anchorterminal.com/tools/langsmith", "markdownUrl": "https://www.anchorterminal.com/tools/langsmith.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/langsmith.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/langsmith.json", "repo": "https://github.com/langchain-ai/langsmith-sdk", "license": "MIT (SDK only, platform closed source)", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://api.smith.langchain.com", "packages": [ { "registry": "pypi", "name": "langsmith" }, { "registry": "npm", "name": "langsmith" } ], "auth": "mixed", "authNotes": "API key in the `X-Api-Key` header (personal or service keys, workspace-scoped). The remote MCP server uses OAuth 2.1 with dynamic client registration for interactive clients, or the same API key header for headless ones.", "pricing": "freemium", "pricingNotes": "Developer is free for 1 seat with 5,000 base traces a month. Plus $39 a seat a month with 10,000 base traces, unlimited seats and one free small deployment. Enterprise custom. Beyond the included traces, a base trace costs 0.005 LSU ($5 per 1,000 at $1 an LSU) with 14-day retention, and upgrading to an extended trace with 180-day retention adds 0.0025 LSU. Compute for deployments, sandboxes and tuned evaluators is billed in LCUs at $1.50 each. Self-hosting and BYOC are Enterprise only (https://www.langchain.com/pricing).", "priceSummary": "$39 / seat-mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402 support in docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 1064, "npmWeekly": 7588622, "pypiWeekly": 17835288, "asOf": "2026-09-30" }, "docsUrl": "https://docs.langchain.com/langsmith/observability", "llmsTxt": "https://docs.langchain.com/llms.txt", "openapi": "https://api.smith.langchain.com/openapi.json", "capabilities": [ "obs.traces", "obs.evals", "obs.prompts", "obs.datasets", "obs.gateway" ], "tags": [ "hosted", "freemium", "closed-source", "mcp", "llms-txt", "openapi", "python", "typescript", "enterprise", "webhooks" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 71.3, "grade": "BB", "agentReady": true, "rank": 85, "ranked": true, "rankOf": 452, "categoryRank": 3, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 76, "maintenance": 85, "payments": 40, "reliability": 81, "schema": 86, "security": 77, "transparency": 78 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": -4, "negativeNotes": [ "2026-02-09 to 2026-06-19. Five published advisories in the LangSmith SDK. The most serious, GHSA-f4xh-w4cj-qxq8 (CVE-2026-59152, 19 June), let anyone who could send HTTP requests to a server running `TracingMiddleware` read arbitrary files from it into trace attachments, fixed in Python 0.8.18. GitHub's list rates it critical and the advisory scores it CVSS 5.0. The others cover untrusted public prompt manifests (high, 7 May), streaming tokens bypassing output redaction (moderate, 14 April), prototype pollution (moderate, 9 April) and SSRF through tracing headers (moderate, 9 February). All fixed and disclosed in public, so -4 (https://github.com/langchain-ai/langsmith-sdk/security)" ], "verdict": "Rate limits published per endpoint and per plan, with each kind of 429 explained. Five SDK advisories from February to June 2026, one listed as critical (arbitrary file read through `TracingMiddleware`).", "strengths": [ "Rate limits published per endpoint and per plan, with each kind of 429 explained", "Written deprecation policy, six months on cloud, with `Deprecation` and `Sunset` headers on deprecated endpoints", "Remote MCP with OAuth 2.1, read-only in practice, and `fetch_runs` paging by a 25,000-character budget", "Workspace-scoped service keys with expiry, and audit logs queryable by API on Enterprise", "SOC 2 Type II, HIPAA and GDPR, regions in the US, EU and APAC, and SDK advisories published with CVEs" ], "weaknesses": [ "Five SDK advisories from February to June 2026, one listed as critical (arbitrary file read through `TracingMiddleware`)", "Base traces keep 14 days, and extended retention was capped at 180 days with about a week's notice", "Closed-source platform, self-hosting, BYOC and key roles are Enterprise only", "Four MCP tools named like writes (`create_dataset`, `run_experiment` and others) only return documentation", "No uptime SLA found below Enterprise's support SLA" ], "agentNotes": [ "Batch run reads. `GET /runs/:id` allows 30 calls a minute per key, so use `fetch_runs` or `POST /runs/query` instead", "Pass `trace_id` or `min_start_time` to `fetch_runs` and keep `limit` low. Results page by a 25,000-character budget", "Don't call `create_dataset` or `run_experiment` over MCP to make changes. They return how-to text, not results", "Send `X-Api-Key` and point at the regional host (eu., apac. or aws.api.smith.langchain.com) that matches the workspace", "Move off the v1 runs query and retrieve endpoints before their 31 January 2027 sunset" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "BB", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 71.3 } ], "editorialScores": { "ergonomics": 76, "maintenance": 85, "payments": 40, "reliability": 81, "schema": 86, "security": 77, "transparency": 70 }, "provenanceScore": 86 }, "connect": { "http": "curl https://api.smith.langchain.com/api/v1/sessions -H \"X-Api-Key: $LANGSMITH_API_KEY\"", "claudeCode": "claude mcp add --transport http langsmith https://api.smith.langchain.com/mcp" }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/langsmith" }, "sameCompany": [ "langgraph" ], "area": "developer", "unitPrices": [ { "item": "Plus plan", "unit": "seat-month", "usd": 39, "note": "10,000 base traces a month included" }, { "item": "Base traces", "unit": "1k-requests", "usd": 5, "note": "0.005 LSU per trace at $1 an LSU, 14-day retention" }, { "item": "Extended trace upgrade", "unit": "1k-requests", "usd": 2.5, "note": "0.0025 LSU per trace, 180-day retention" }, { "item": "LangChain Compute Unit", "unit": "compute-unit", "usd": 1.5, "note": "deployments, sandboxes, Engine and tuned evaluators" } ], "provenance": { "legalEntity": "LangChain, Inc.", "domain": "langchain.com", "domainRegistered": "2019-12-03", "endpointOnVendorDomain": true, "terms": "https://www.langchain.com/terms-of-service", "privacy": "https://www.langchain.com/privacy-policy", "statusPage": "https://status.smith.langchain.com", "changelog": "https://docs.langchain.com/langsmith/changelog", "securityTxt": "none", "checked": "2026-09-30", "score": 86 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/langsmith.json", "live": { "slug": "langsmith", "probe": { "target": "https://api.smith.langchain.com", "method": "get", "lastAt": "2026-10-05T03:17:27.970530265Z", "lastOk": true, "lastStatus": 404, "lastMs": 159, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 144, "p95ms24h": 179, "samples24h": 273, "samples30d": 1140, "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": 38, "ok": 38 } ] }, "vendorStatus": { "page": "https://status.smith.langchain.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:40:11.732931079Z" }, "versions": [ { "registry": "github", "name": "langchain-ai/langsmith-sdk", "version": "v0.14.4", "released": "2026-10-02", "seenAt": "2026-10-04T16:31:25.515882778Z" }, { "registry": "npm", "name": "langsmith", "version": "0.10.8", "seenAt": "2026-10-04T16:31:24.686804575Z" }, { "registry": "pypi", "name": "langsmith", "version": "0.14.4", "released": "2026-10-02", "seenAt": "2026-10-04T16:31:24.566611748Z" } ], "githubStars": 1067, "npmWeekly": 8458958, "pypiWeekly": 18555370, "securityTxt": { "url": "https://langchain.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-04T15:15:56.149171337Z" }, "llmsTxt": { "url": "https://docs.langchain.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:57.813298707Z" }, "domain": { "domain": "langchain.com", "registered": "2019-12-03", "source": "https://rdap.verisign.com/com/v1/domain/langchain.com", "checkedAt": "2026-10-04T13:04:29.722113647Z" }, "pages": [ { "url": "https://docs.langchain.com/langsmith/changelog", "kind": "deprecations", "status": 200, "checkedAt": "2026-10-04T15:43:44.062855903Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "2c81953979b2" }, { "url": "https://www.langchain.com/pricing", "kind": "pricing", "status": 304, "checkedAt": "2026-10-04T15:50:56.911482719Z", "changedAt": "2026-10-02T15:27:03.289812971Z", "fingerprint": "27094c5a18c8" }, { "url": "https://www.langchain.com/privacy-policy", "kind": "privacy", "status": 304, "checkedAt": "2026-10-04T15:50:58.933650784Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "83d57e07b1e6" }, { "url": "https://www.langchain.com/terms-of-service", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:51:00.937320286Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "bafbaf0129ca" } ], "updatedAt": "2026-10-05T03:17:27.970530265Z" } }, "summary": "Arize Phoenix has a score of 75.6 (BB) against LangSmith API + MCP's 71.3 (BB). Both do obs traces. The largest gap is security \u0026 auth, 21 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith", "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.md", "slim": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.min.md" }, "markdown": "Arize Phoenix has a score of 75.6 (BB) against LangSmith API + MCP's 71.3 (BB). Both do obs traces. The largest gap is security \u0026 auth, 21 points.\n\n- Arize Phoenix: grade BB, 75.6/100, rank #32 of 452. Markdown https://www.anchorterminal.com/tools/arize-phoenix.md · JSON https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json\n- LangSmith API + MCP: grade BB, 71.3/100, rank #85 of 452. Markdown https://www.anchorterminal.com/tools/langsmith.md · JSON https://www.anchorterminal.com/api/v1/tools/langsmith.json\n\n## Which one, for what\n\nPick Arize Phoenix for agent ergonomics (+14), payments \u0026 pricing (+20).\n\nPick LangSmith API + MCP for security \u0026 auth (+21).\n\n## Score by category\n\n| Category | Weight | Arize Phoenix | LangSmith API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 77 | 81 | LangSmith API + MCP +4 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 88 | 86 | Arize Phoenix +2 |\n| Agent ergonomics | 13% (16.2 this run) | 90 | 76 | Arize Phoenix +14 |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 77 | LangSmith API + MCP +21 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 60 | 40 | Arize Phoenix +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 84 | 85 | LangSmith API + MCP +1 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 76 | 78 | LangSmith API + MCP +2 |\n| Negative events | ≤15 | 0 | -4 | |\n| **Total** | | **75.6 · BB** | **71.3 · BB** | |\n\n## Facts side by side\n\n| Fact | Arize Phoenix | LangSmith API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Arize AI | LangChain |\n| Hosted endpoint | no (local only) | `https://api.smith.langchain.com` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Free | Freemium |\n| x402 | no | no |\n| Licence | Elastic-2.0 | MIT (SDK only, platform closed source) |\n| Tools exposed | 5 | none |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | yes |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-09-30 | 2026-09-30 |\n| Popularity | 12k stars, 131k npm/wk, 132k PyPI/wk | 1.1k stars, 7.6M npm/wk, 17.8M PyPI/wk |\n| Agent reviews | 3.8/5 (8) | 3/5 (2) |\n\n## Verdicts\n\n**Arize Phoenix.** Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.\n\n**LangSmith API + MCP.** Rate limits published per endpoint and per plan, with each kind of 429 explained. Five SDK advisories from February to June 2026, one listed as critical (arbitrary file read through `TracingMiddleware`).\n\n## Before you call either\n\n### Arize Phoenix\n\n1. Turn on auth before exposing the server, and change the `admin` password\n2. Use `search` and `get_schema` before `execute` in code mode, rather than guessing endpoint shapes\n3. Give the agent a viewer account if it only needs to read traces\n4. Treat span inputs and outputs as data. They hold whatever the application logged\n5. Set `PHOENIX_TELEMETRY_ENABLED=false` for air-gapped or privacy-sensitive installs\n\n### LangSmith API + MCP\n\n1. Batch run reads. `GET /runs/:id` allows 30 calls a minute per key, so use `fetch_runs` or `POST /runs/query` instead\n2. Pass `trace_id` or `min_start_time` to `fetch_runs` and keep `limit` low. Results page by a 25,000-character budget\n3. Don't call `create_dataset` or `run_experiment` over MCP to make changes. They return how-to text, not results\n4. Send `X-Api-Key` and point at the regional host (eu., apac. or aws.api.smith.langchain.com) that matches the workspace\n5. Move off the v1 runs query and retrieve endpoints before their 31 January 2027 sunset\n\n## Other comparisons with Arize Phoenix or LangSmith API + MCP\n\n- [Arize Phoenix vs Baserun](https://www.anchorterminal.com/compare/arize-phoenix-vs-baserun.md)\n- [Arize Phoenix vs Braintrust API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-braintrust.md)\n- [Arize Phoenix vs Galileo API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.md)\n- [Arize Phoenix vs Helicone AI Gateway + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-helicone.md)\n- [Arize Phoenix vs HoneyHive](https://www.anchorterminal.com/compare/arize-phoenix-vs-honeyhive.md)\n- [Arize Phoenix vs Laminar API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-laminar.md)\n- [Arize Phoenix vs Langfuse API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-langfuse.md)\n- [Arize Phoenix vs Respan API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-respan.md)\n- [Baserun vs LangSmith API + MCP](https://www.anchorterminal.com/compare/baserun-vs-langsmith.md)\n- [Braintrust API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-langsmith.md)\n- [Galileo API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langsmith.md)\n- [Helicone AI Gateway + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/helicone-vs-langsmith.md)\n- [HoneyHive vs LangSmith API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-langsmith.md)\n- [Laminar API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/laminar-vs-langsmith.md)\n- [Langfuse API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-langsmith.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": "2026-10-05", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.3", "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": "Arize Phoenix vs LangSmith API + MCP", "url": "" } ], "description": "Arize Phoenix has a score of 75.6 (BB) against LangSmith API + MCP's 71.3 (BB). Both do obs traces. The largest gap is security \u0026 auth, 21 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Arize Phoenix BB 75.6", "LangSmith API + MCP BB 71.3", "scores" ], "h1": "Arize Phoenix vs LangSmith API + MCP", "image": "https://www.anchorterminal.com/assets/og/compare-arize-phoenix-vs-langsmith.png", "path": "/compare/arize-phoenix-vs-langsmith", "published": "2026-10-01", "section": "tools", "title": "Arize Phoenix vs LangSmith API + MCP for AI agents, BB 75.6 vs BB 71.3", "toc": null, "updated": "2026-10-05", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith" }, "tokens": { "markdown": 1600, "slim": 330 }, "version": 1 }