AgenticWire test record: fastmcp-vs-fastapi-mcp
Article: https://www.agenticwire.news/article/fastmcp-vs-fastapi-mcp
Machine and versions: see results.json (machine field).

Harness script (experiment/run.sh):

#!/usr/bin/env bash
# fastmcp vs fastapi-mcp: does a plain install of each actually work today?
#
# Self-contained: builds its own venvs, assumes only python3 + uv on PATH.
# Re-run:  node blog-app/scripts/pipeline/bench.mjs drafts/fastmcp-vs-fastapi-mcp
set -uo pipefail
cd "$(dirname "$0")"
log() { echo "$@" >&2; }
emit() { echo "$1"; }

WORK="${TMPDIR:-/tmp}/famcp-bench-$$"
mkdir -p "$WORK"
trap 'rm -rf "$WORK"' EXIT

log "building venvs in $WORK"
uv venv --python 3.13 "$WORK/fmcp" >&2 2>/dev/null
uv venv --python 3.13 "$WORK/famcp" >&2 2>/dev/null
VIRTUAL_ENV="$WORK/fmcp" uv pip install fastmcp fastapi >&2 2>/dev/null
VIRTUAL_ENV="$WORK/famcp" uv pip install fastapi-mcp fastapi >&2 2>/dev/null

PY_F="$WORK/fmcp/bin/python"
PY_A="$WORK/famcp/bin/python"

# --- versions, from a plain install today ---
V_FMCP=$($PY_F -c "import importlib.metadata as m; print(m.version('fastmcp'))")
V_FAMCP=$($PY_A -c "import importlib.metadata as m; print(m.version('fastapi-mcp'))")
V_MCP_IN_FAMCP=$($PY_A -c "import importlib.metadata as m; print(m.version('mcp'))")
emit "{\"metric\":\"fastmcp_version_resolved\",\"value\":\"$V_FMCP\",\"note\":\"uv pip install fastmcp\"}"
emit "{\"metric\":\"fastapi_mcp_version_resolved\",\"value\":\"$V_FAMCP\",\"note\":\"uv pip install fastapi-mcp\"}"
emit "{\"metric\":\"mcp_version_pulled_by_fastapi_mcp\",\"value\":\"$V_MCP_IN_FAMCP\",\"note\":\"transitive dep, fastapi-mcp declares mcp>=1.12.0 with no upper bound\"}"

# --- days since fastapi-mcp's last PyPI release (free, public API) ---
UPLOAD=$(curl -sS -m 20 https://pypi.org/pypi/fastapi-mcp/json | python3 -c "import json,sys; print(json.load(sys.stdin)['urls'][0]['upload_time'])" 2>/dev/null || echo "")
if [ -n "$UPLOAD" ]; then
  DAYS=$(python3 -c "
from datetime import datetime
u = datetime.fromisoformat('$UPLOAD')
print((datetime.utcnow() - u).days)
")
  emit "{\"metric\":\"fastapi_mcp_days_since_last_release\",\"value\":$DAYS,\"unit\":\"days\",\"note\":\"PyPI upload_time for $V_FAMCP was $UPLOAD\"}"
fi

# --- does a fresh install of fastapi-mcp actually work? (the finding) ---
cat > "$WORK/conv_famcp.py" <<'PY'
from fastapi import FastAPI
from fastapi_mcp import FastApiMCP

app = FastAPI()

@app.get("/items/{item_id}")
def get_item(item_id: int):
    return {"item_id": item_id}

mcp = FastApiMCP(app)
mcp.mount()
print("OK", "/mcp" in [r.path for r in app.routes])
PY
if $PY_A "$WORK/conv_famcp.py" >"$WORK/famcp_fresh.out" 2>"$WORK/famcp_fresh.err"; then
  emit "{\"metric\":\"fastapi_mcp_fresh_install_works\",\"value\":true}"
else
  ERR=$(tail -1 "$WORK/famcp_fresh.err" | sed 's/"/\\"/g')
  emit "{\"metric\":\"fastapi_mcp_fresh_install_works\",\"value\":false,\"note\":\"$ERR\"}"
fi

# --- pin mcp<2 (the constraint fastapi-mcp's own metadata technically allows): does that fix it? ---
VIRTUAL_ENV="$WORK/famcp" uv pip install "mcp<2" >&2 2>/dev/null
V_MCP_PINNED=$($PY_A -c "import importlib.metadata as m; print(m.version('mcp'))")
if $PY_A "$WORK/conv_famcp.py" >"$WORK/famcp_pinned.out" 2>"$WORK/famcp_pinned.err"; then
  emit "{\"metric\":\"fastapi_mcp_works_with_mcp_lt_2\",\"value\":true,\"note\":\"pinned mcp==$V_MCP_PINNED\"}"
else
  emit "{\"metric\":\"fastapi_mcp_works_with_mcp_lt_2\",\"value\":false}"
fi
if grep -qi "deprecat" "$WORK/famcp_pinned.err" 2>/dev/null; then
  emit "{\"metric\":\"fastapi_mcp_mount_deprecation_warning\",\"value\":true,\"note\":\"$(grep -i deprecat "$WORK/famcp_pinned.err" | head -1 | sed 's/\"/\\\"/g')\"}"
fi

# --- fastmcp.from_fastapi() conversion ---
cat > "$WORK/conv_fmcp.py" <<'PY'
import asyncio
from fastapi import FastAPI
from fastmcp import FastMCP

app = FastAPI()

@app.get("/items/{item_id}")
def get_item(item_id: int):
    return {"item_id": item_id}

mcp = FastMCP.from_fastapi(app=app)
tools = asyncio.run(mcp.list_tools())
print(len(tools), [t.name for t in tools])
PY
if OUT=$($PY_F "$WORK/conv_fmcp.py" 2>&1); then
  N=$(echo "$OUT" | head -1 | cut -d' ' -f1)
  emit "{\"metric\":\"fastmcp_from_fastapi_works\",\"value\":true,\"note\":\"converted $N tool(s) from a single-route FastAPI app\"}"
else
  emit "{\"metric\":\"fastmcp_from_fastapi_works\",\"value\":false}"
fi

# --- OAuth provider surface: article claims 3 dedicated + "documented compatibility" with others ---
N_PROVIDERS=$($PY_F -c "
import pkgutil, fastmcp.server.auth.providers as p
print(len([m for m in pkgutil.iter_modules(p.__path__)]))
")
emit "{\"metric\":\"fastmcp_dedicated_oauth_providers\",\"value\":$N_PROVIDERS,\"note\":\"submodules under fastmcp.server.auth.providers\"}"
if $PY_A -c "from fastapi_mcp import AuthConfig" >/dev/null 2>&1; then R=true; else R=false; fi
emit "{\"metric\":\"fastapi_mcp_has_dedicated_provider_layer\",\"value\":$R,\"note\":\"AuthConfig relies on FastAPI's own dependency-injected auth, not named OAuth providers\"}"

log "done"