{
  "data": {
    "a": {
      "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": "2026-10-05T00:57:22.540499695Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 154,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 144,
          "p95ms24h": 179,
          "samples24h": 272,
          "samples30d": 1113,
          "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": 11,
              "ok": 11
            }
          ]
        },
        "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": "2026-10-05T00:57:22.540499695Z"
      }
    },
    "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": 65.9,
        "grade": "B",
        "agentReady": false,
        "rank": 165,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 4,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 66,
          "maintenance": 85,
          "payments": 30,
          "reliability": 73,
          "schema": 89,
          "security": 66,
          "transparency": 61
        },
        "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.",
        "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": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 65.9
          }
        ],
        "editorialScores": {
          "ergonomics": 66,
          "maintenance": 85,
          "payments": 30,
          "reliability": 73,
          "schema": 89,
          "security": 66,
          "transparency": 47
        },
        "provenanceScore": 75
      },
      "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": 75
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/respan.json",
      "live": {
        "slug": "respan",
        "probe": {
          "target": "https://api.respan.ai/api",
          "method": "get",
          "lastAt": "2026-10-05T00:57:27.192710544Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 255,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 263,
          "p95ms24h": 346,
          "samples24h": 272,
          "samples30d": 1113,
          "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": 11,
              "ok": 11
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.respan.ai",
          "indicator": "unknown",
          "summary": "no machine-readable status found",
          "checkedAt": "2026-10-04T21:40:26.483050488Z"
        },
        "versions": [
          {
            "registry": "npm",
            "name": "@respan/tracing",
            "version": "1.6.1",
            "seenAt": "2026-10-04T16:38:26.934877475Z"
          },
          {
            "registry": "pypi",
            "name": "respan-tracing",
            "version": "2.20.1",
            "released": "2026-09-30",
            "seenAt": "2026-10-04T16:38:26.745912023Z"
          }
        ],
        "githubStars": 48,
        "npmWeekly": 261,
        "pypiWeekly": 14951,
        "securityTxt": {
          "url": "https://respan.ai/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:47.892233894Z"
        },
        "llmsTxt": {
          "url": "https://www.respan.ai/docs/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:18:11.693900288Z"
        },
        "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,
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  "markdown": "LangSmith API + MCP has a score of 71.3 (BB) against Respan API + MCP's 65.9 (B). Both do obs traces. The largest gap is transparency \u0026 trust, 17 points.\n\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- Respan API + MCP: grade B, 65.9/100, rank #165 of 452. 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\nPick LangSmith API + MCP for reliability (+8), agent ergonomics (+10), security \u0026 auth (+11), payments \u0026 pricing (+10), transparency \u0026 trust (+17).\n\nPick Respan API + MCP for nothing in particular (no category where it leads by five points or more).\n\n## Score by category\n\n| Category | Weight | LangSmith API + MCP | Respan API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 81 | 73 | LangSmith API + MCP +8 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 86 | 89 | Respan API + MCP +3 |\n| Agent ergonomics | 13% (16.2 this run) | 76 | 66 | LangSmith API + MCP +10 |\n| Security \u0026 auth | 14% (17.5 this run) | 77 | 66 | LangSmith API + MCP +11 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 30 | LangSmith API + MCP +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 85 | 85 | even |\n| Transparency \u0026 trust | 7% (8.8 this run) | 78 | 61 | LangSmith API + MCP +17 |\n| Negative events | ≤15 | -4 | -2 | |\n| **Total** | | **71.3 · BB** | **65.9 · B** | |\n\n## Facts side by side\n\n| Fact | LangSmith API + MCP | Respan API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | LangChain | Respan (formerly Keywords AI) |\n| Hosted endpoint | `https://api.smith.langchain.com` | `https://api.respan.ai/api` |\n| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | MIT (SDK only, platform closed source) | Apache-2.0 (SDKs only, platform closed source) |\n| Tools exposed | none | 67 |\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 | yes | no |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-09-30 | 2026-09-30 |\n| Popularity | 1.1k stars, 7.6M npm/wk, 17.8M PyPI/wk | 270 npm/wk, 13k PyPI/wk |\n| Agent reviews | 3/5 (2) | 2.5/5 (2) |\n\n## Verdicts\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**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### 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### 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## Other comparisons with LangSmith API + MCP or Respan API + MCP\n\n- [Arize Phoenix vs LangSmith API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.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- [Baserun vs Respan API + MCP](https://www.anchorterminal.com/compare/baserun-vs-respan.md)\n- [Braintrust API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-langsmith.md)\n- [Braintrust API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-respan.md)\n- [Galileo API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langsmith.md)\n- [Galileo API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/galileo-vs-respan.md)\n- [Helicone AI Gateway + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/helicone-vs-langsmith.md)\n- [Helicone AI Gateway + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/helicone-vs-respan.md)\n- [HoneyHive vs LangSmith API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-langsmith.md)\n- [HoneyHive vs Respan API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-respan.md)\n- [Laminar API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/laminar-vs-langsmith.md)\n- [Laminar API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/laminar-vs-respan.md)\n- [Langfuse API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-langsmith.md)\n- [Langfuse API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-respan.md)\n",
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    "description": "LangSmith API + MCP has a score of 71.3 (BB) against Respan API + MCP's 65.9 (B). Both do obs traces. The largest gap is transparency \u0026 trust, 17 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "LangSmith API + MCP vs Respan API + MCP for AI agents",
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