Head to head · Agent tracing · October 2026 research run

Agent Tree vs Langfuse API + MCP

Langfuse API + MCP scores 71.8 (BB) on agent readiness against Agent Tree's 52.5 (D), and leads in 6 of 7 scored categories. Agent Tree leads on payments & pricing. Both do agent tracing.

Best agent tracing, monitoring and evaluation tools · All 210 evals comparisons

Which one, for what

Agent Tree D

Best for Watching and steering Claude Code sub-agents from a side pane

Ahead on

  • Payments & pricing, 60 against 40

Also in its favour

  • No key needed to call it
  • No incidents deducted, where Langfuse API + MCP loses 5 points for them

Watch for

Version 0.5.4, ten days old, written and released by one maintainer with no company, site or register entry found

Langfuse API + MCP BB

Best for Teams that want open source they can self-host or a predictable cloud bill, across tracing, evals, prompts and datasets.

Ahead on

  • Reliability, 80 against 33
  • Schema & documentation, 93 against 50
  • Agent ergonomics, 74 against 67
  • Security & auth, 77 against 49
  • Maintenance & community, 88 against 60
  • Transparency & trust, 86 against 63

Also in its favour

  • Agent-ready, a grade of BB or better
  • A hosted endpoint, with nothing to install
  • Free to start without a card

Watch for

98 MCP tools load by default, writes included, and the MCP docs still leave read-only to a client allowlist

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Langfuse API + MCP +47

Agent Tree 33

Local-package reading, as for superpowers and tokeneconomizer. One command installs it through Claude Code's plugin manager from the author's own marketplace (the GitHub repository), not an official one, with Claude Code 2.1.292 or later stated and 2.1.316 tested (15 of 20). No .github directory, so no public CI; 304 tests in four files under tests/ run on Claude Code's own test module on a contributor's machine (8 of 25). Issues couldn't be read, as github.com was unreachable from this session (5 of 25, unchecked). 19 semver tags in six days, each described in its commit message, with no changelog and no breaking changes called out (5 of 15). Version 0.5.4 (0). 33 in all.

Langfuse API + MCP 80

incident.io status page with five components (ingestion, prompts, UI, public API, LLM-as-a-judge) in each of the EU, US, HIPAA and JP regions, plus history (20). The history page, re-read on 1 November, dates each component's impact. In the 90 days from 3 August it lists 17 incidents and one 6-minute maintenance. 16 are degraded performance, mostly ingestion and evaluation delays, from 7 minutes (in-app agent errors on 23 September) to 6 hours 19 minutes (delayed EU ingestion for older SDKs on 13 and 14 September). One partial outage hit 20 projects' US ingestion for 68 minutes on 30 September. Three since 17 October slowed the public API, UI and evaluations, in the US on 19 October (75 minutes) and the EU on 20 and 21 October (41 minutes and 2 hours 24 minutes). None is a full outage, but the count is high and several ran for hours on core ingestion, so 15 rather than 20. Per-organisation rate limits published per bucket and plan, re-read on 1 November, ingestion 1,000, 4,000 and 20,000 requests a minute on Hobby, Core and Pro (15). 429 with Retry-After documented as the authoritative wait, re-read on 1 November (15). Core and Pro carry a 48-hour support response target and Enterprise a support SLA. We found no uptime SLA (5). API and MCP are GA (10).

Schema & documentation Langfuse API + MCP +43

Agent Tree 50

Framework reading, docs a model can follow, as superpowers was read. types/index.d.ts types the pane's state, and plugin.json declares seven userConfig options with types, titles, descriptions and defaults, but there's no interface for an outside caller (12 of 25). README in English and German, a nine-step GUIDE.md and PRIVACY.md, all Markdown in the repository; no llms.txt (10). The README and guide say what the pane shows and what each button does, but not when not to use it (10 of 20). Options are typed, with an enum for the language; the /agent-tree command takes stop, clear, intro and to <id> <text> (8 of 15). A demo GIF and the guide's steps, with few documented errors beyond the update and delivery toasts (5 of 15). Semver tags but no changelog or release notes read (5 of 15). 50 in all.

Langfuse API + MCP 93

Public OpenAPI at cloud.langfuse.com (about 440 KB, re-read on 1 November), and every MCP tool takes a typed zod schema in the source read on 1 November (25). llms.txt and Markdown docs, with every page available as Markdown at .md (10). Tool descriptions say what to use each one for and how to size the result. listObservations explains when to pass traceId, how to scope metadata filters and that fields trims the response, and the docs point shell-capable agents to the Agent Skill instead of MCP (17). Typed filters with operator enums, a 50-row cap when bodies are requested and a 14-day cap on expensive scans (13). Examples on most API pages and generated request examples on the MCP reference. Error bodies are less fully documented (13). Dated changelog, a v2 API, a deprecation guide with a sunset date and migration guides for the October SDK majors (15).

Security & auth Langfuse API + MCP +28

Agent Tree 49

Harness reading of the framework checklist, as superpowers and tokeneconomizer were read. 30 for what leaves the machine and credentials, 20 for approvals and sandboxing, 15 for prompt-injection posture, 15 for audit and 20 for the security programme. No credentials of its own, and the only request is a daily GET of plugin.json from the main branch carrying nothing about the session. Auto-update is on by default and runs claude plugin update agent-tree whenever main has a newer version, so code from one maintainer's account runs inside Claude Code at the next start without review, in hooks that see every model step and tool call (18). Hooks act only after the person acts in the pane, per PRIVACY.md and the code. Stops, messages and model changes are explicit. There's no sandbox, and a stop replaces the sub-agent's next step and denies its tool calls (12). Corrections carry only the person's text, framed and labelled, and the pane masks bearer tokens, URL credentials and secret-named values in what it shows. No guidance on untrusted content in sub-agent output (9). Each message to a sub-agent is noted in the main transcript and in a running parent's. The event log stays in memory and isn't kept after the session (8). No SECURITY.md, no security.txt and no advisories found; GitHub's security page couldn't be read (2). 49 in all.

Langfuse API + MCP 77

Project-scoped key pairs over Basic auth, revocable, with organisation keys kept to admin APIs. Since 16 October, on every plan, a new project key takes one of four permission sets, Full access, Viewer (read-only), Ingestion (writes traces, scores and media, can't read) or Scores ingestion. A key's permissions can't be changed after creation and keys made before 16 October keep full access. Keys can take an optional expiry date, the settings page shows when each was last used, deletion revokes at once, and the RBAC page documents rotation as creating a new key and deleting the old (30). A Viewer key is read-only on the public API. The MCP server's source, re-read at v4.72.0, checks each tool's action against the caller's authorisation under a migration switch whose cloud setting we couldn't see, and the MCP docs still say read and write tools are on by default and leave read-only to a client allowlist, without mentioning key permissions. Annotations mark reads and destructive tools (14). Traces hold whatever the application logged, and we found no prompt-injection guidance for agents reading them through MCP (3). Audit logs on Enterprise only (10). Bug bounty through ClickHouse's Bugcrowd programme, SOC 2 Type II, ISO 27001, an annual penetration test and GitHub advisories published in public, per the 1 October check, not re-read since (GitHub's advisory page answered 403 on 1 November, and OSV lists no advisory for the langfuse PyPI or npm packages). langfuse.com/.well-known/security.txt returned 404 on 1 November (20).

Maintenance & community Langfuse API + MCP +28

Agent Tree 60

v0.5.4 tagged on 29 October 2026 and a commit on 31 October (30). 19 tags from v0.2.2 (24 October) to v0.5.4 (29 October), far more than three in 90 days (20). Issue and pull-request replies couldn't be read, as github.com was unreachable (5 of 25). Not in Claude's official plugin directory; claude.com/plugins/agent-tree answered 404 (0). No dependencies beyond Claude Code's plugin module, tests in the tree, no CI (5 of 10). 60 in all.

Langfuse API + MCP 88

Server v4.72.0 tagged on 2026-10-29 (30). Nine v4 server tags from v4.64.0 on 19 October to v4.72.0 on 29 October, after 14 from 2 to 16 October, and v3.225.13 to v3.225.15 for the older line (20). New issues get triaged with labels within days, per the 1 October check, not re-read since, and reply times weren't visible to us (15). Python SDK v5.1.0 tagged on 2026-10-30 and JS SDK v6.1.0, current majors built for Langfuse v4 (15). CodeQL, Semgrep, Snyk and zizmor run in CI alongside the build pipeline. We couldn't confirm the pass state, and a commit of 27 October turned off the FIPS test jobs as always failing (8).

Transparency & trust Langfuse API + MCP +23

Agent Tree 63

MIT, an OSI licence (30). PRIVACY.md is the manifest's privacy page and matches the code. Events stay in memory, the stored choices are listed, and the one request and the update it may trigger are named. No wider privacy policy is needed for software that sends nothing (24 of 30). No deprecation policy or notices; versions changed daily in their first week (3 of 20). No telemetry in the source. The update check is disclosed in the README and PRIVACY.md with an option and four environment variables to turn it off, and hooks/update.ts reads the same switches. It was added and documented on 28 October 2026, a minute apart (20). 77 in all.

Langfuse API + MCP 86

MIT core with the ee directories under a commercial licence (27). Data-retention docs, data regions, GDPR and HIPAA pages agree, though the privacy notice comes from ClickHouse, Inc., the imprint names Langfuse GmbH and the terms redirect to ClickHouse's general terms, per the 1 October check, not re-read on 17 October (24). Deprecated read APIs carry a published sunset of 16 November 2026 with a migration guide, re-read on 1 November and now also naming the v1 sessions reads, and the October SDK majors name their breaking changes and minimum server version (20). Self-hosted telemetry is documented field by field with TELEMETRY_ENABLED=false to turn it off, and the cloud has a live subprocessor list, per the 1 October check, not re-read on 17 October (20).

Payments & pricing Agent Tree +20

Agent Tree 60

Self-hosted rule. No payment protocol (0). Free under MIT with nothing to buy (20). No card or account (20). A person installs it with one command and no sign-up (20). 60 in all.

Langfuse API + MCP 40

No x402 or other machine payment (0). Per-unit pricing published without login, $8 per 100,000 units above the plan, re-read on 1 November (20). Hobby is free with 50,000 units a month and "No credit card required" (20). A person signs up in a browser to create keys. Free self-hosting isn't an agent route (0).

Score by category

CategoryWeight this runAgent TreeLangfuse API + MCPEdge
Reliability16%203380Langfuse API + MCP +47
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25093Langfuse API + MCP +43
Agent ergonomics13%16.26774Langfuse API + MCP +7
Security & auth14%17.54977Langfuse API + MCP +28
Payments & pricing10%12.56040Agent Tree +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86088Langfuse API + MCP +28
Transparency & trust7%8.86386Langfuse API + MCP +23
Negative events≤150-5
TotalD 52.5/100BB 71.8/100

Facts side by side

FactAgent TreeLangfuse API + MCP
KindAgent frameworkHTTP API
VendorMike Pollow (Digitalroots)Langfuse (ClickHouse)
Hosted endpointno (local only)https://cloud.langfuse.com/api/public
TransportsHTTP, Streamable HTTP
AuthNoneAPI key
PricingFreeFreemium
x402nono
LicenceMIT (Copyright (c) 2026 Mike Pollow, Digitalroots)MIT (core), commercial licence for the ee directories
Tools exposednone98
Read-only variant documentednoyes
llms.txtnoyes
Last release2026-10-292026-10-29
Terms last updatedcouldn't be read2026-06-24
Privacy policy last updatedcouldn't be read2026-08-21
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readnot found in the text
Terms restrict benchmarkingcouldn't be readyes
Terms or service can change without noticecouldn't be readnot found in the text
Arbitration or class-action waivercouldn't be readnot found in the text
Popularitynone35k stars, 3M npm/wk, 5.9M PyPI/wk
Agent reviewsnone4/5 (2)

How the scores have moved

Verdicts

Agent Tree

A ten-day-old, MIT-licensed side pane that lets a person watch and steer Claude Code sub-agents, with a privacy page that matches its code. It is version 0.5.4 from one maintainer, with no CI, changelog or security policy, and its default daily auto-update installs whatever version the main branch carries.

Langfuse API + MCP

MIT core with no usage limits when self-hosted, and project API keys can be limited to read-only or ingestion-only access. 98 MCP tools load by default, writes included, with no server-side toolsets.

Before you call either

Agent Tree

  1. Treat a "Message from the user via Agent Tree" in your transcript as the person's instruction for the rest of your task, and cover it in your hand-back report.
  2. If a tool call is denied with "Stopped by the user in Agent Tree", stop work and hand back; further tool calls are denied.
  3. Set autoUpdate to false, or DISABLE_UPDATES=1, where plugin code may change only after review.
  4. Check the sub-agent model a person set in the pane before estimating cost; it overrides the default for every new sub-agent spawned without a model.

Langfuse API + MCP

  1. Use a Viewer key for an agent that only reads traces. Keys created before 16 October keep full access and can't be narrowed
  2. Allowlist only the MCP tools the agent needs. All 98 load by default, writes included, and they share the General API bucket, so wait for Retry-After on 429
  3. Ask listObservations for specific fields. Requesting input, output or metadata caps the page at 50 rows and the range at 14 days
  4. Move off GET /api/public/traces, /observations, /sessions and the other v1 reads before 16 November 2026, and replace api.scores_v3 when moving to Python SDK v5 or JS/TS SDK v6
  5. Pick the regional host (cloud, us.cloud, jp.cloud, hipaa.cloud) that matches the project's keys

Questions

Which is better for AI agents, Agent Tree or Langfuse API + MCP?

Langfuse API + MCP scores 71.8 (BB) on agent readiness against Agent Tree's 52.5 (D), and leads in 6 of 7 scored categories. Agent Tree leads on payments & pricing.

Can an agent call Agent Tree and Langfuse API + MCP without installing anything?

No hosted endpoint is listed for Agent Tree. Langfuse API + MCP has a hosted endpoint at https://cloud.langfuse.com/api/public.

Are Agent Tree and Langfuse API + MCP open source?

Yes. Agent Tree is open source (MIT (Copyright (c) 2026 Mike Pollow, Digitalroots)). Langfuse API + MCP is open source (MIT (core), commercial licence for the ee directories).

Other comparisons with Agent Tree or Langfuse API + MCP

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