RepoRadar
Leave a Tip
Item detail
github.com

PrefectHQ/fastmcp

PrefectHQ/fastmcp is a framework that RepoRadar is tracking in its Radar section, currently rated Gold tier with a 'try now' verdict. Its strongest signal is workflow potential, scored 10.0 out of 10.

Open on GitHub →Back to radar
Score8.8
Popularity82.0
Riskconditional
TierGold
Score breakdown
Usefulness9.0
Novelty8.0
Momentum8.0
Maturity8.5
Open-source/build8.4
Evidence7.2
Workflow potential10.0
Setup ease6.4

Popularity is tracked separately. Support, ads, sponsorships, and tips never affect these signals.

Why it matters

Useful for developers who want to ship MCP integrations without hand-rolling transport plumbing, tool metadata, and server lifecycle code every time.

Who should use it

Python developers building MCP servers internal platform teams agent-tooling builders automation engineers

Who should skip it

Move on from PrefectHQ/fastmcp if the licensing terms, language support, or platform requirements do not fit your project.

About this signal

PrefectHQ/fastmcp is tracked by RepoRadar as a framework in the Radar section. First seen 2026-06-19; the source record was last checked on 2026-06-19. The current verdict is 'try now' with a Gold tier and moderate setup difficulty. PrefectHQ/fastmcp leads on workflow potential (10.0) and practical usefulness (9.0); its lowest signal is setup ease (6.4), so factor that in before investing setup time. This page summarizes the public evidence on the linked source page and states where additional review is still needed.

How this item is evaluated

The PrefectHQ/fastmcp record combines a 8.8/10 composite score with separate popularity (82.0), risk (conditional), and setup (moderate) signals. See the scoring methodology for the current weights and evidence definitions.

Putting this into practice? Read How to vet an AI agent or MCP server before you wire it in for the checklist behind this score.

Risk explanation

If you expose a FastMCP server beyond localhost, review authentication and tool scope first because MCP servers can surface local files, secrets, or actions to remote clients.

Evidence links
Closest alternatives / related signals
mcp python developer-tools agents framework
Verification record

What RepoRadar actually verified

Tested in a bounded workflow

Bounded representative workflow retained by RepoRadar verification harness. Last checked 2026-07-14T05:43:50.718258Z.

passed · cohort-20260712-fastmcp-local-server

Tester
RepoRadar automated local verification harness
Started
2026-07-13T10:35:22.580960Z
Completed
2026-07-13T10:35:27.438649Z
Environment
Windows 10 AMD64; Python 3.11.9; credential-stripped child environment; disposable home/cache
Install/setup time
1 minute(s)
Evidence scope
Bounded representative workflow
Cleanup
Per-check temporary home and work directory removed. Shared cohort package cache removed.
Actions exercised
  • Created a disposable home, work directory, and isolated package cache with credential-like environment variables excluded.
  • Registered a typed severity(latency_ms) tool on a local FastMCP server.
  • Opened FastMCP's in-memory Client, listed the exposed tool, called it with 750 ms latency, and asserted the structured result was page.
  • Executed bounded check: Register a typed FastMCP severity tool, discover it through an in-memory client, and invoke it with fixture input.
  • Captured the complete sanitized stdout, stderr, exit status, artifact checks, and 4.86-second wall time.
Observed results
  • Command exited 0 after 4.86 seconds.
  • The client discovered exactly one registered tool and the end-to-end MCP call returned the expected page decision.
  • Expected marker 'CHECK_OK tools=1 result=page' was observed in retained output.
  • Validated result.json: 2 required marker(s) present and 0 excluded marker(s) absent; size and SHA-256 are retained.
Observed strengths
  • FastMCP converted a typed Python function into a discoverable tool and completed a real client call without manual protocol framing or a network listener.
Friction
  • The workflow still needed an async client lifecycle and explicit result-data handling; production transport and security configuration remain separate work.
  • Setup or runtime emitted 7 stderr line(s); the complete warnings/errors are preserved in the retained log.
Limitations
  • The in-memory transport validates tool registration, discovery, schema conversion, and invocation but not stdio/HTTP transport, authentication, middleware, deployment, concurrency, or a remote MCP host.
  • This credential-free disposable workflow does not establish production scale, model quality, reliability under sustained use, or team adoption.

Pricing assessment: The in-memory FastMCP client/server workflow used the local open-source package and no paid host or model.

Privacy assessment: The synthetic latency value stayed inside an in-process transport; no socket, hosted MCP service, provider credential, or model request was involved.

Open retained test log →

passed · cohort-20260714-fastmcp-local-server

Tester
codex-local-audit
Started
2026-07-14T05:43:45.204692Z
Completed
2026-07-14T05:43:50.718258Z
Environment
Windows 10 AMD64; Python 3.11.9; credential-stripped child environment; disposable home/cache
Install/setup time
1 minute(s)
Evidence scope
Bounded representative workflow
Cleanup
Per-check temporary home and work directory removed. Shared cohort package cache removed.
Actions exercised
  • Created a disposable home, work directory, and isolated package cache with credential-like environment variables excluded.
  • Registered a typed severity(latency_ms) tool on a local FastMCP server.
  • Opened FastMCP's in-memory Client, listed the exposed tool, called it with 750 ms latency, and asserted the structured result was page.
  • Executed bounded check: Register a typed FastMCP severity tool, discover it through an in-memory client, and invoke it with fixture input.
  • Captured the complete sanitized stdout, stderr, exit status, artifact checks, and 5.51-second wall time.
Observed results
  • Command exited 0 after 5.51 seconds.
  • The client discovered exactly one registered tool and the end-to-end MCP call returned the expected page decision.
  • Expected marker 'CHECK_OK tools=1 result=page' was observed in retained output.
  • Validated result.json: 2 required marker(s) present and 0 excluded marker(s) absent; size and SHA-256 are retained.
Observed strengths
  • FastMCP converted a typed Python function into a discoverable tool and completed a real client call without manual protocol framing or a network listener.
Friction
  • The workflow still needed an async client lifecycle and explicit result-data handling; production transport and security configuration remain separate work.
  • Setup or runtime emitted 11 stderr line(s); the complete warnings/errors are preserved in the retained log.
Limitations
  • The in-memory transport validates tool registration, discovery, schema conversion, and invocation but not stdio/HTTP transport, authentication, middleware, deployment, concurrency, or a remote MCP host.
  • This credential-free disposable workflow does not establish operator use, production scale, model quality, reliability under sustained use, or team adoption.

Pricing assessment: The in-memory FastMCP client/server workflow used the local open-source package and no paid host or model.

Privacy assessment: The synthetic latency value stayed inside an in-process transport; no socket, hosted MCP service, provider credential, or model request was involved.

Open retained test log →

Verification sources

Longitudinal intelligence

How this decision record is moving

Raw history JSON →

46 dated snapshots retained from 2026-06-19 through 2026-08-13; see the snapshot index for explicit coverage gaps. Stars, version, release, pricing, integration, risk, maintenance, verdict, score, and momentum fields remain explicit even when a source has not reported them. Repository momentum is a normalized 0–10 RepoRadar signal; GitHub stars appear only where the popularity monitor retained exact timestamped observations.

RepoRadar score8.8 current · +0.0 net
Repository momentum9.6 current · +1.6 net
GitHub stars (observed)27,205 current · +1,015 net
GitHub stars27,205 exact observation
Versionv3.4.7
Last release2026-08-10T21:17:13Z
Maintenanceactive
Current riskconditional
Current verdicttry now
Pricing baselineNo structured commercial pricing baseline
Pricing checkedNot applicable or not recorded
Pricing freshnessNo dated commercial pricing review
Integrations baselineModel Context Protocol

Recent dated points

DateScoreMomentumStarsRiskVerdictMaintenance
2026-08-138.89.627,205conditionaltry nowactive
2026-08-128.89.627,190conditionaltry nowactive
2026-08-118.89.627,171conditionaltry nowactive
2026-08-108.89.627,149conditionaltry nowactive
2026-08-098.89.627,132conditionaltry nowactive
2026-08-088.89.627,117conditionaltry nowactive
2026-08-078.89.627,030conditionaltry nowactive
2026-08-068.88.0Not recordedconditionaltry nownot recorded
2026-08-058.88.0Not recordedconditionaltry nownot recorded
2026-08-048.89.627,030conditionaltry nowactive
2026-08-038.89.627,030conditionaltry nowactive
2026-08-028.89.627,019conditionaltry nowactive

Why the record changed

stars changed

Stars changed: 27190 → 27205.

verification changed

Verification changed: Re-tested recently → Tested in a bounded workflow.

stars changed

Stars changed: 27171 → 27190.

version changed

Version changed: v4.0.0b2 → v3.4.7.

stars changed

Stars changed: 27149 → 27171.

stars changed

Stars changed: 27132 → 27149.

stars changed

Stars changed: 27117 → 27132.

version changed

Version changed: v4.0.0b1 → v4.0.0b2.

stars changed

Stars changed: 27030 → 27117.

stars changed

Stars changed: 27019 → 27030.

stars changed

Stars changed: 27005 → 27019.

stars changed

Source-observed stars changed: 26999 → 27005. This reports the retained observation delta and does not infer why the upstream change occurred.