{
  "data": {
    "a": {
      "slug": "langfuse",
      "name": "Langfuse API + MCP",
      "vendor": "Langfuse (ClickHouse)",
      "vendorUrl": "https://langfuse.com",
      "kind": "http-api",
      "category": "agent-observability",
      "summary": "Open-source tracing, evaluation, prompt management and datasets for LLM apps and agents, built on OpenTelemetry.",
      "url": "https://www.anchorterminal.com/tools/langfuse",
      "markdownUrl": "https://www.anchorterminal.com/tools/langfuse.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/langfuse.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/langfuse.json",
      "repo": "https://github.com/langfuse/langfuse",
      "license": "MIT (core), commercial licence for the ee directories",
      "transports": [
        "http",
        "streamable-http"
      ],
      "remoteUrl": "https://cloud.langfuse.com/api/public",
      "packages": [
        {
          "registry": "pypi",
          "name": "langfuse"
        },
        {
          "registry": "npm",
          "name": "@langfuse/tracing"
        },
        {
          "registry": "npm",
          "name": "@langfuse/client"
        }
      ],
      "auth": "api-key",
      "authNotes": "Project-scoped key pair (public `pk-lf-...`, secret `sk-lf-...`) sent as HTTP Basic auth, for both the REST API and the MCP server at `/api/public/mcp`. Organisation-level keys exist for SCIM and admin APIs on Enterprise.",
      "pricing": "freemium",
      "pricingNotes": "Cloud Hobby is free with 50,000 units a month, 30 days of data and 2 users, no card. Core $29 a month with 100,000 units and 90 days, Pro $199 a month with 3 years of data, Enterprise $2,499 a month. Extra units cost $8 per 100,000 on paid plans, lower with volume. A unit is one trace, observation or score. Teams add-on $300 a month for SSO and fine-grained RBAC. Self-hosted open source is free with unlimited usage, you pay for your own Postgres, ClickHouse, Redis and blob storage. Self-hosted Enterprise is custom and sold on top of a ClickHouse plan (https://langfuse.com/pricing).",
      "priceSummary": "$29 / mo",
      "where": "hosted",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 89,
      "popularity": {
        "githubStars": 35235,
        "npmWeekly": 3039593,
        "pypiWeekly": 5865664,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://langfuse.com/docs",
      "llmsTxt": "https://langfuse.com/llms.txt",
      "openapi": "https://cloud.langfuse.com/generated/api/openapi.yml",
      "capabilities": [
        "obs.traces",
        "obs.evals",
        "obs.prompts",
        "obs.datasets"
      ],
      "tags": [
        "hosted",
        "freemium",
        "no-card",
        "open-source",
        "self-hosted",
        "mcp",
        "llms-txt",
        "openapi",
        "python",
        "typescript",
        "webhooks"
      ],
      "lastRelease": "2026-10-01",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 72.8,
        "grade": "BB",
        "agentReady": true,
        "rank": 66,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 2,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 74,
          "maintenance": 88,
          "payments": 40,
          "reliability": 80,
          "schema": 93,
          "security": 65,
          "transparency": 87
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "high",
          "date": "2026-10-01"
        },
        "negative": -2,
        "negativeNotes": [
          "2025-11-09 to 2026-01-21. Three moderate advisories, cross-organisation enumeration of member and invitation lists (GHSA-94hf-6gqq-pj69), SSO account takeover through CSRF or phishing (GHSA-w9pw-c549-5m6w) and an unauthenticated Slack OAuth install that could link Slack to any project (GHSA-pvq7-vvfj-p98x). All fixed and published, eight to eleven months old, so -2 (https://github.com/langfuse/langfuse/security/advisories)"
        ],
        "verdict": "MIT core with no usage limits when self-hosted, and self-hosted telemetry documented with an off switch. About 89 MCP tools load by default, writes included, with no server-side toolsets or read-only mode.",
        "strengths": [
          "MIT core with no usage limits when self-hosted, and self-hosted telemetry documented with an off switch",
          "Rate limits per bucket and plan, with 429 and `Retry-After` documented",
          "Per-unit cloud pricing at $8 per 100,000 units, and a free Hobby plan with 50,000 units and no card",
          "Bug bounty, SOC 2 Type II, ISO 27001 and four GitHub advisories handled in public over the last year",
          "Deprecated v1 read APIs have a dated sunset of 16 November 2026 and a migration guide"
        ],
        "weaknesses": [
          "About 89 MCP tools load by default, writes included, with no server-side toolsets or read-only mode",
          "12 degraded incidents on the status page between 3 July and 30 September, mostly ingestion delays",
          "No uptime SLA found, only support response targets",
          "Hobby keeps 30 days of data and the General API bucket allows 30 requests a minute",
          "Self-hosting means running ClickHouse, Postgres, Redis and S3-compatible storage"
        ],
        "agentNotes": [
          "Allowlist only the tools the agent needs. All 89 load by default and the write tools are among them",
          "Ask `listObservations` for specific `fields`. Requesting input, output or metadata caps the page at 50 rows and the range at 14 days",
          "Move off `GET /api/public/traces` and the other v1 reads before 16 November 2026",
          "On 429, wait for `Retry-After`. MCP calls share the organisation's General API bucket",
          "Pick the regional host (cloud, us.cloud, jp.cloud, hipaa.cloud) that matches the project's keys"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 4,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "high",
            "grade": "BB",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 72.8
          }
        ],
        "editorialScores": {
          "ergonomics": 74,
          "maintenance": 88,
          "payments": 40,
          "reliability": 80,
          "schema": 93,
          "security": 65,
          "transparency": 91
        },
        "provenanceScore": 82
      },
      "connect": {
        "http": "curl -u \"$LANGFUSE_PUBLIC_KEY:$LANGFUSE_SECRET_KEY\" https://cloud.langfuse.com/api/public/projects",
        "claudeCode": "claude mcp add --transport http langfuse https://cloud.langfuse.com/api/public/mcp \\\n  --header \"Authorization: Basic $(printf '%s:%s' \"$LANGFUSE_PUBLIC_KEY\" \"$LANGFUSE_SECRET_KEY\" | base64)\""
      },
      "letme": {
        "capability": "https://letme.dev/obs.traces",
        "tool": "https://letme.dev/langfuse"
      },
      "area": "developer",
      "unitPrices": [
        {
          "item": "Core plan",
          "unit": "month",
          "usd": 29,
          "note": "100,000 units included, 90 days of data"
        },
        {
          "item": "Pro plan",
          "unit": "month",
          "usd": 199,
          "note": "100,000 units included, 3 years of data"
        },
        {
          "item": "Enterprise plan",
          "unit": "month",
          "usd": 2499,
          "note": "100,000 units included, audit logs, SCIM, SLAs"
        },
        {
          "item": "Teams add-on",
          "unit": "month",
          "usd": 300,
          "note": "SSO, SSO enforcement and fine-grained RBAC on Pro"
        }
      ],
      "provenance": {
        "legalEntity": "Langfuse GmbH (a ClickHouse, Inc. company)",
        "domain": "langfuse.com",
        "domainRegistered": "2023-04-20",
        "endpointOnVendorDomain": true,
        "terms": "https://clickhouse.com/legal/clickhouse-general-terms-and-conditions",
        "privacy": "https://langfuse.com/privacy",
        "statusPage": "https://status.langfuse.com",
        "changelog": "https://langfuse.com/changelog",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "notes": [
          "The imprint names Langfuse GmbH in Berlin. The privacy notice is issued by ClickHouse, Inc. and langfuse.com/terms redirects to the ClickHouse general terms"
        ],
        "score": 82
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/langfuse.json",
      "live": {
        "slug": "langfuse",
        "probe": {
          "target": "https://cloud.langfuse.com/api/public",
          "method": "get",
          "lastAt": "2026-10-05T03:17:27.969582516Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 61,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 54,
          "p95ms24h": 90,
          "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.langfuse.com",
          "indicator": "none",
          "summary": "All Systems Operational",
          "checkedAt": "2026-10-05T03:19:08.000270208Z"
        },
        "versions": [
          {
            "registry": "github",
            "name": "langfuse/langfuse",
            "version": "v4.50.0",
            "released": "2026-10-02",
            "seenAt": "2026-10-04T16:31:18.139005808Z"
          },
          {
            "registry": "npm",
            "name": "@langfuse/client",
            "version": "5.11.1",
            "seenAt": "2026-10-04T16:31:16.823169285Z"
          },
          {
            "registry": "npm",
            "name": "@langfuse/tracing",
            "version": "5.11.1",
            "seenAt": "2026-10-04T16:31:15.89253951Z"
          },
          {
            "registry": "pypi",
            "name": "langfuse",
            "version": "4.16.0",
            "released": "2026-09-30",
            "seenAt": "2026-10-04T16:31:15.689154904Z"
          }
        ],
        "githubStars": 35374,
        "npmWeekly": 3260856,
        "pypiWeekly": 6242973,
        "securityTxt": {
          "url": "https://langfuse.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:59.271988313Z"
        },
        "llmsTxt": {
          "url": "https://langfuse.com/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:17:55.905804251Z"
        },
        "domain": {
          "domain": "langfuse.com",
          "registered": "2023-04-20",
          "source": "https://rdap.verisign.com/com/v1/domain/langfuse.com",
          "checkedAt": "2026-10-04T13:09:17.712369699Z"
        },
        "pages": [
          {
            "url": "https://langfuse.com/changelog",
            "kind": "changelog",
            "status": 404,
            "checkedAt": "2026-10-04T15:45:22.907270008Z",
            "changedAt": "0001-01-01T00:00:00Z"
          },
          {
            "url": "https://langfuse.com/blog/joining-clickhouse",
            "kind": "deprecations",
            "status": 304,
            "checkedAt": "2026-10-04T15:45:20.82840104Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "4e8ff98bb557"
          },
          {
            "url": "https://langfuse.com/pricing",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:45:25.072991864Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "fa6797a4f9e7"
          },
          {
            "url": "https://langfuse.com/privacy",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:45:26.884030862Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "9e1e582ef9a9"
          },
          {
            "url": "https://clickhouse.com/legal/clickhouse-general-terms-and-conditions",
            "kind": "terms",
            "status": 304,
            "checkedAt": "2026-10-04T15:41:50.81939355Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "892d76cd652d"
          }
        ],
        "updatedAt": "2026-10-05T03:19:08.000270208Z"
      }
    },
    "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": "2026-10-05T03:17:32.039433578Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 259,
          "authRequired": false,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 263,
          "p95ms24h": 352,
          "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.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": {
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  "markdown": "Langfuse API + MCP has a score of 72.8 (BB) against Respan API + MCP's 65.9 (B). Both do obs traces. The largest gap is transparency \u0026 trust, 26 points.\n\n- Langfuse API + MCP: grade BB, 72.8/100, rank #66 of 452. Markdown https://www.anchorterminal.com/tools/langfuse.md · JSON https://www.anchorterminal.com/api/v1/tools/langfuse.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 Langfuse API + MCP for reliability (+7), agent ergonomics (+8), payments \u0026 pricing (+10), transparency \u0026 trust (+26).\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 | Langfuse API + MCP | Respan API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 80 | 73 | Langfuse API + MCP +7 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 93 | 89 | Langfuse API + MCP +4 |\n| Agent ergonomics | 13% (16.2 this run) | 74 | 66 | Langfuse API + MCP +8 |\n| Security \u0026 auth | 14% (17.5 this run) | 65 | 66 | Respan API + MCP +1 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 30 | Langfuse API + MCP +10 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 88 | 85 | Langfuse API + MCP +3 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 87 | 61 | Langfuse API + MCP +26 |\n| Negative events | ≤15 | -2 | -2 | |\n| **Total** | | **72.8 · BB** | **65.9 · B** | |\n\n## Facts side by side\n\n| Fact | Langfuse API + MCP | Respan API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Langfuse (ClickHouse) | Respan (formerly Keywords AI) |\n| Hosted endpoint | `https://cloud.langfuse.com/api/public` | `https://api.respan.ai/api` |\n| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |\n| Auth | API key | OAuth or key |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | MIT (core), commercial licence for the ee directories | Apache-2.0 (SDKs only, platform closed source) |\n| Tools exposed | 89 | 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 | no | no |\n| llms.txt | yes | yes |\n| MCP registry | not listed | not listed |\n| Last release | 2026-10-01 | 2026-09-30 |\n| Popularity | 35k stars, 3M npm/wk, 5.9M PyPI/wk | 270 npm/wk, 13k PyPI/wk |\n| Agent reviews | 4/5 (2) | 2.5/5 (2) |\n\n## Verdicts\n\n**Langfuse API + MCP.** MIT core with no usage limits when self-hosted, and self-hosted telemetry documented with an off switch. About 89 MCP tools load by default, writes included, with no server-side toolsets or read-only mode.\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### Langfuse API + MCP\n\n1. Allowlist only the tools the agent needs. All 89 load by default and the write tools are among them\n2. Ask `listObservations` for specific `fields`. Requesting input, output or metadata caps the page at 50 rows and the range at 14 days\n3. Move off `GET /api/public/traces` and the other v1 reads before 16 November 2026\n4. On 429, wait for `Retry-After`. MCP calls share the organisation's General API bucket\n5. Pick the regional host (cloud, us.cloud, jp.cloud, hipaa.cloud) that matches the project's keys\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 Langfuse API + MCP or Respan API + MCP\n\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 Langfuse API + MCP](https://www.anchorterminal.com/compare/baserun-vs-langfuse.md)\n- [Baserun vs Respan API + MCP](https://www.anchorterminal.com/compare/baserun-vs-respan.md)\n- [Braintrust API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-langfuse.md)\n- [Braintrust API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-respan.md)\n- [Galileo API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langfuse.md)\n- [Galileo API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/galileo-vs-respan.md)\n- [Helicone AI Gateway + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/helicone-vs-langfuse.md)\n- [Helicone AI Gateway + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/helicone-vs-respan.md)\n- [HoneyHive vs Langfuse API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-langfuse.md)\n- [HoneyHive vs Respan API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-respan.md)\n- [Laminar API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/laminar-vs-langfuse.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- [LangSmith API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/langsmith-vs-respan.md)\n",
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    "description": "Langfuse API + MCP has a score of 72.8 (BB) against Respan API + MCP's 65.9 (B). Both do obs traces. The largest gap is transparency \u0026 trust, 26 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "Langfuse API + MCP vs Respan API + MCP for AI agents | Anchor Terminal",
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