{
  "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": "galileo",
      "name": "Galileo API + MCP",
      "vendor": "Galileo (now Splunk Agent Observability, Cisco)",
      "vendorUrl": "https://galileo.ai",
      "kind": "http-api",
      "category": "agent-observability",
      "summary": "Hosted tracing, evaluation metrics and guardrails for LLM apps and agents, with a REST API, Python and TypeScript SDKs and an 8-tool MCP server in preview.",
      "url": "https://www.anchorterminal.com/tools/galileo",
      "markdownUrl": "https://www.anchorterminal.com/tools/galileo.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/galileo.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/galileo.json",
      "repo": "https://github.com/rungalileo/galileo-python",
      "license": "Apache-2.0 (SDKs only, platform closed source)",
      "transports": [
        "http",
        "streamable-http"
      ],
      "remoteUrl": "https://api.galileo.ai/v2",
      "packages": [
        {
          "registry": "pypi",
          "name": "galileo"
        },
        {
          "registry": "npm",
          "name": "galileo"
        }
      ],
      "auth": "api-key",
      "authNotes": "API key in a header. The current OpenAPI spec names it `Splunk-AO-API-Key` and older Galileo docs `Galileo-API-Key`. The API also issues a JWT from `/login/api_key` that expires after 24 hours and accepts HTTP Basic with a username and password. The MCP server takes the same API key header. New SaaS accounts on Splunk Observability Cloud use `https://app.{realm}.observability.splunkcloud.com/ao/api/` and Splunk's own authentication. Self-hosted deployments use their own api.* host.",
      "pricing": "freemium",
      "pricingNotes": "Free plan with 5,000 traces a month, unlimited users and unlimited custom evals. Pro $100 a month billed yearly with 50,000 traces, then priced by trace volume with no published rate. Enterprise is custom with unlimited traces, custom rate limits and hosted, VPC or on-prem deployment. The pricing page doesn't mention Splunk, but the docs say customers onboarded after 2026-08-07 should use the Splunk docs (https://galileo.ai/pricing).",
      "priceSummary": "$100 / mo",
      "where": "hosted",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 8,
      "popularity": {
        "githubStars": null,
        "npmWeekly": 1431,
        "pypiWeekly": 6160,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://docs.galileo.ai",
      "llmsTxt": "https://docs.galileo.ai/llms.txt",
      "openapi": "https://api.galileo.ai/public/v2/openapi.json",
      "capabilities": [
        "obs.traces",
        "obs.evals",
        "obs.prompts",
        "obs.datasets"
      ],
      "tags": [
        "hosted",
        "freemium",
        "mcp",
        "llms-txt",
        "openapi",
        "python",
        "typescript",
        "closed-source",
        "enterprise"
      ],
      "lastRelease": "2026-10-01",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 48,
        "grade": "D",
        "agentReady": false,
        "rank": 378,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 8,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 73,
          "maintenance": 74,
          "payments": 20,
          "reliability": 18,
          "schema": 79,
          "security": 33,
          "transparency": 56
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "OpenAPI 3.1 spec with 184 paths and 244 operations. No status page, no published rate limits and no SLA.",
        "strengths": [
          "OpenAPI 3.1 spec with 184 paths and 244 operations",
          "Error catalogue of 111 entries with HTTP status, fix and a retriable flag",
          "Free plan with 5,000 traces a month and unlimited users",
          "TypeScript SDK released three times in September 2026, most recently 2.3.2 on 1 October",
          "Enterprise deployment in your VPC or on-prem"
        ],
        "weaknesses": [
          "No status page, no published rate limits and no SLA",
          "Split between Galileo and Splunk since 7 August 2026, with two doc sites, two API hosts and no timeline for the old ones",
          "MCP server in preview with 8 tools, only `Get Signals` reads production data",
          "No security page, trust portal, security.txt or certification claim found, and the privacy policy dates from November 2024",
          "Python SDK quiet since 30 July and its CHANGELOG.md stuck at v0.10.0"
        ],
        "agentNotes": [
          "Check which side the account lives on first. Pre-August Galileo accounts use api.galileo.ai, Splunk SaaS accounts use app.{realm}.observability.splunkcloud.com/ao/api/",
          "Send the key as `Splunk-AO-API-Key`. The current spec no longer lists `Galileo-API-Key`",
          "Page list endpoints with `limit` and `starting_token`",
          "Use the error catalogue's retriable flag to decide whether to retry. 429s carry no documented `Retry-After`",
          "Use the REST API to read traces. The MCP server mostly creates datasets and prompts"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 2.5,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "D",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 48
          }
        ],
        "editorialScores": {
          "ergonomics": 73,
          "maintenance": 74,
          "payments": 20,
          "reliability": 18,
          "schema": 79,
          "security": 33,
          "transparency": 36
        },
        "provenanceScore": 76
      },
      "connect": {
        "http": "curl https://api.galileo.ai/v2/current_user -H \"Galileo-API-Key: $GALILEO_API_KEY\"",
        "claudeCode": "claude mcp add --transport http --header \"Galileo-API-Key: $GALILEO_API_KEY\" galileo https://api.galileo.ai/mcp/http/mcp",
        "config": {
          "mcpServers": {
            "galileo": {
              "headers": {
                "Accept": "text/event-stream",
                "Galileo-API-Key": "${GALILEO_API_KEY}"
              },
              "type": "http",
              "url": "https://api.galileo.ai/mcp/http/mcp"
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/obs.traces",
        "tool": "https://letme.dev/galileo"
      },
      "alsoIn": [
        "guardrails"
      ],
      "area": "developer",
      "unitPrices": [
        {
          "item": "Pro plan",
          "unit": "month",
          "usd": 100,
          "note": "billed yearly, 50,000 traces a month"
        }
      ],
      "provenance": {
        "legalEntity": "Galileo Technologies, Inc.",
        "domain": "galileo.ai",
        "domainRegistered": "2020-05-05",
        "endpointOnVendorDomain": true,
        "terms": "https://galileo.ai/terms-of-service",
        "privacy": "https://galileo.ai/privacy-policy",
        "statusPage": "",
        "changelog": "https://docs.galileo.ai/release-notes",
        "securityTxt": "none",
        "checked": "2026-09-30",
        "notes": [
          "Now owned by Cisco and sold as Splunk Agent Observability; the terms still name Galileo Technologies, Inc."
        ],
        "score": 76
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/galileo.json",
      "live": {
        "slug": "galileo",
        "probe": {
          "target": "https://api.galileo.ai/v2",
          "method": "get",
          "lastAt": "2026-10-05T00:15:23.903726283Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 1422,
          "authRequired": false,
          "uptime24h": 99.26,
          "uptime30d": 99.73,
          "p50ms24h": 312,
          "p95ms24h": 3892,
          "samples24h": 272,
          "samples30d": 1105,
          "days": [
            {
              "date": "2026-09-30",
              "probes": 35,
              "ok": 35
            },
            {
              "date": "2026-10-01",
              "probes": 276,
              "ok": 276
            },
            {
              "date": "2026-10-02",
              "probes": 248,
              "ok": 247
            },
            {
              "date": "2026-10-03",
              "probes": 271,
              "ok": 271
            },
            {
              "date": "2026-10-04",
              "probes": 272,
              "ok": 270
            },
            {
              "date": "2026-10-05",
              "probes": 3,
              "ok": 3
            }
          ]
        },
        "versions": [
          {
            "registry": "github",
            "name": "rungalileo/galileo-python",
            "version": "v2.6.0",
            "released": "2026-07-30",
            "seenAt": "2026-10-04T16:27:40.611176298Z"
          },
          {
            "registry": "npm",
            "name": "galileo",
            "version": "2.3.2",
            "seenAt": "2026-10-04T16:27:40.188712083Z"
          },
          {
            "registry": "pypi",
            "name": "galileo",
            "version": "2.6.0",
            "released": "2026-07-30",
            "seenAt": "2026-10-04T16:27:40.002157835Z"
          }
        ],
        "githubStars": 22,
        "npmWeekly": 1892,
        "securityTxt": {
          "url": "https://galileo.ai/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:15:43.807289994Z"
        },
        "llmsTxt": {
          "url": "https://docs.galileo.ai/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:17:48.251773467Z"
        },
        "domain": {
          "domain": "galileo.ai",
          "registered": "2020-05-05",
          "source": "https://rdap.identitydigital.services/rdap/domain/galileo.ai",
          "checkedAt": "2026-10-04T13:06:13.135112782Z"
        },
        "pages": [
          {
            "url": "https://docs.galileo.ai/release-notes",
            "kind": "deprecations",
            "status": 200,
            "checkedAt": "2026-10-04T15:43:38.210171478Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "0771d4784c19"
          },
          {
            "url": "https://galileo.ai/pricing",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:51.381606205Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "0145c8cf98fd"
          },
          {
            "url": "https://galileo.ai/privacy-policy",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:53.544097308Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "0a4347a8061e"
          },
          {
            "url": "https://galileo.ai/terms-of-service",
            "kind": "terms",
            "status": 304,
            "checkedAt": "2026-10-04T15:44:55.585915991Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "fe70a53f84a7"
          }
        ],
        "updatedAt": "2026-10-05T00:15:23.903726283Z"
      }
    },
    "summary": "Arize Phoenix has a score of 75.6 (BB) against Galileo API + MCP's 48 (D). Both do obs traces. The largest gap is reliability, 59 points."
  },
  "kind": "anchor.page",
  "links": {
    "api": "https://www.anchorterminal.com/api/v1/index.json",
    "html": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo",
    "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.json",
    "llms": "https://www.anchorterminal.com/llms.txt",
    "markdown": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.md",
    "slim": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.min.md"
  },
  "markdown": "Arize Phoenix has a score of 75.6 (BB) against Galileo API + MCP's 48 (D). Both do obs traces. The largest gap is reliability, 59 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- Galileo API + MCP: grade D, 48/100, rank #378 of 452. Markdown https://www.anchorterminal.com/tools/galileo.md · JSON https://www.anchorterminal.com/api/v1/tools/galileo.json\n\n## Which one, for what\n\nPick Arize Phoenix for reliability (+59), schema \u0026 documentation (+9), agent ergonomics (+17), security \u0026 auth (+23), payments \u0026 pricing (+40), maintenance \u0026 community (+10), transparency \u0026 trust (+20).\n\nPick Galileo 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 | Arize Phoenix | Galileo API + MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 77 | 18 | Arize Phoenix +59 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 88 | 79 | Arize Phoenix +9 |\n| Agent ergonomics | 13% (16.2 this run) | 90 | 73 | Arize Phoenix +17 |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 33 | Arize Phoenix +23 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 60 | 20 | Arize Phoenix +40 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 84 | 74 | Arize Phoenix +10 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 76 | 56 | Arize Phoenix +20 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **75.6 · BB** | **48 · D** | |\n\n## Facts side by side\n\n| Fact | Arize Phoenix | Galileo API + MCP |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Arize AI | Galileo (now Splunk Agent Observability, Cisco) |\n| Hosted endpoint | no (local only) | `https://api.galileo.ai/v2` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |\n| Auth | OAuth or key | API key |\n| Pricing | Free | Freemium |\n| x402 | no | no |\n| Licence | Elastic-2.0 | Apache-2.0 (SDKs only, platform closed source) |\n| Tools exposed | 5 | 8 |\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 | 2026-09-30 | 2026-10-01 |\n| Popularity | 12k stars, 131k npm/wk, 132k PyPI/wk | 1.4k npm/wk, 6.2k PyPI/wk |\n| Agent reviews | 3.8/5 (8) | 2.5/5 (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**Galileo API + MCP.** OpenAPI 3.1 spec with 184 paths and 244 operations. No status page, no published rate limits and no SLA.\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### Galileo API + MCP\n\n1. Check which side the account lives on first. Pre-August Galileo accounts use api.galileo.ai, Splunk SaaS accounts use app.{realm}.observability.splunkcloud.com/ao/api/\n2. Send the key as `Splunk-AO-API-Key`. The current spec no longer lists `Galileo-API-Key`\n3. Page list endpoints with `limit` and `starting_token`\n4. Use the error catalogue's retriable flag to decide whether to retry. 429s carry no documented `Retry-After`\n5. Use the REST API to read traces. The MCP server mostly creates datasets and prompts\n\n## Other comparisons with Arize Phoenix or Galileo 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 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 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 Galileo API + MCP](https://www.anchorterminal.com/compare/baserun-vs-galileo.md)\n- [Braintrust API + MCP vs Galileo API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-galileo.md)\n- [Galileo API + MCP vs Helicone AI Gateway + MCP](https://www.anchorterminal.com/compare/galileo-vs-helicone.md)\n- [Galileo API + MCP vs HoneyHive](https://www.anchorterminal.com/compare/galileo-vs-honeyhive.md)\n- [Galileo API + MCP vs Laminar API + MCP](https://www.anchorterminal.com/compare/galileo-vs-laminar.md)\n- [Galileo API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langfuse.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",
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        "name": "Arize Phoenix vs Galileo API + MCP",
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    "description": "Arize Phoenix has a score of 75.6 (BB) against Galileo API + MCP's 48 (D). Both do obs traces. The largest gap is reliability, 59 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "Arize Phoenix vs Galileo API + MCP for AI agents, BB 75.6 vs D 48",
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