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The CodSpeed MCP server gives AI-powered tools direct access to your performance data — benchmark runs, comparisons, and flamegraphs — so you can investigate regressions, explore profiling results, and review performance changes without leaving your editor or chat interface. The server follows the Model Context Protocol (MCP) specification and is hosted by CodSpeed at 
https://mcp.codspeed.io/mcp

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Getting started

Install the plugin from the official Claude plugins marketplace:
/plugin install codspeed@claude-plugins-official
The plugin installs both the MCP server and agent skills automatically.
Alternatively, you can add the MCP server directly:
claude mcp add --transport http CodSpeed https://mcp.codspeed.io/mcp

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Alternative: auto-detect with add-mcp

If your tool supports it, you can use add-mcp to automatically detect installed agents and configure them: 
npx add-mcp https://mcp.codspeed.io/mcp --name CodSpeed

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Example prompts

Once connected, you can ask your AI assistant questions like:
  • “Explain the regression on the feat/my-great-feature branch.”
  • “Make my foo_bar function faster.”
  • “What are the hottest functions in the bench_foo benchmark?”
  • “Analyze the flamegraph for bench_parse and refactor the hot path.”
  • “Compare the flamegraphs of bench_serialize between main and feat/new-encoder and explain what changed.”
  • “Find the bottleneck in bench_api_handler and open a PR to fix it.”
Because the MCP server runs inside coding agents, your assistant can cross-reference flamegraph hot spots with your actual source code — then suggest or apply optimizations directly.

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Available tools

The CodSpeed MCP server exposes six tools:
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list_repositories
List all CodSpeed-enabled repositories that you have access to. Returns repository names, visibility, and descriptions.
Input
{}
Output
{
  "repositories": [
    {
      "repository": "CodSpeedHQ/codspeed",
      "visibility": "public",
      "description": "CodSpeed is the all-in-one performance testing toolkit. Optimize code performance and catch regressions early."
    },
    {
      "repository": "CodSpeedHQ/pytest-codspeed",
      "visibility": "public",
      "description": "A pytest plugin to create benchmarks"
    },
    {
      "repository": "CodSpeedHQ/codspeed-rust",
      "visibility": "public",
      "description": "Crates to benchmark your Rust code"
    }
  ]
}
​
list_runs
List recent performance runs for a repository. Returns run IDs, commit hashes, status, event type, branch, and PR information.
Input
{ "repository": "CodSpeedHQ/codspeed", "limit": 5 }
Output
{
  "runs": [
    {
      "id": "6a315367cef14236ed18cd7b",
      "commit": {
        "hash": "7c50010379a4cb2ff1f550e7e8c9790b4391bc8e",
        "message": "fix(valgrind): skip rustup-wrapped proxy in trace-children"
      },
      "date": "2026-06-16T13:45:11.844Z",
      "status": "completed",
      "event": "push",
      "branch": "main"
    },
    {
      "id": "6a315096823c2ab665d8a12b",
      "commit": {
        "hash": "707a61cf1ea55936a2405eabbeddf6b494c44757",
        "message": "fix(valgrind): skip rustup-wrapped proxy in trace-children"
      },
      "date": "2026-06-16T13:33:10.082Z",
      "status": "completed",
      "event": "pull_request",
      "branch": "cod-2850-codspeed-cli-fails-with-rustup-proxy-error",
      "pullRequest": {
        "number": 405,
        "title": "fix(valgrind): skip rustup-wrapped proxy in trace-children"
      }
    }
  ]
}
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get_run
Inspect a single performance run and its benchmark results. Shows benchmark names, identifiers, and values. Accepts a run ID, branch, or defaults to the latest run.
Input
{ "repository": "CodSpeedHQ/codspeed", "run_id": "6a315367cef14236ed18cd7b" }
Output
---
repository: CodSpeedHQ/codspeed
run_id: 6a315367cef14236ed18cd7b
branch: main
commit: 7c50010
date: 2026-06-16T13:45:11.844Z
---

## Benchmarks (7 total)

| Mode       | Benchmark Name          | Benchmark URI                                                            | Value    |
| ---------- | ----------------------- | ------------------------------------------------------------------------ | -------- |
| Memory     | `sleep 1`               | `exec_harness::sleep 1`                                                  | 15.6 KB  |
| WallTime   | `sleep 1`               | `exec_harness::sleep 1`                                                  | 1 s      |
| Simulation | `sleep 1`               | `exec_harness::sleep 1`                                                  | 126.4 µs |
| Simulation | `write_events[10000]`   | `crates/runner-shared/benches/memtrack_writer.rs::write_events[10000]`   | 20 ms    |
| Simulation | `write_events[100000]`  | `crates/runner-shared/benches/memtrack_writer.rs::write_events[100000]`  | 207.3 ms |
| Simulation | `write_events[500000]`  | `crates/runner-shared/benches/memtrack_writer.rs::write_events[500000]`  | 1 s      |
| Simulation | `write_events[1000000]` | `crates/runner-shared/benches/memtrack_writer.rs::write_events[1000000]` | 2.1 s    |
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compare_runs
Compare two performance runs and return a markdown performance report. Shows benchmark-level comparisons including improvements, regressions, and new or missing benchmarks. When the two runs ran in different environments (CPU, OS, runtime version, linked libraries), an “Environment Differences” section is added first.
Input
{
  "repository": "CodSpeedHQ/pytest-codspeed",
  "head_run_id": "6a19d91790da9981fdd07f33",
  "base_run_id": "6a19cc7a6edb082bd37ca2d1"
}
Output
---
repository: CodSpeedHQ/pytest-codspeed
head_run_id: 6a19d91790da9981fdd07f33
head_commit: 7c66604
base_run_id: 6a19cc7a6edb082bd37ca2d1
base_commit: 5db906e
impact: -0.011035181366613855
---

## Environment Differences

> ⚠️ The head and base runs were executed in different environments. Performance
> differences may be caused by environment changes rather than code changes.

### Hardware

- **CPU**: `AMD EPYC 9V74 80-Core Processor` → `AMD EPYC 7763 64-Core Processor`

_…additional environment differences omitted_

## Summary

| Status          | Count |
| --------------- | ----: |
| ⚡ Improvements |    17 |
| ❌ Regressions  |    20 |
| ✅ Unchanged    |   252 |

## Benchmark Results

| Status | Mode     | Benchmark Name                    | `BASE`  | `HEAD`   | Change  |
| ------ | -------- | --------------------------------- | ------- | -------- | ------- |
| ❌     | WallTime | `test_recursive_fibo_20`          | 5.3 ms  | 5.9 ms   | -10.48% |
| ❌     | WallTime | `test_multiprocessing_map[10000]` | 98.1 ms | 108.2 ms | -9.38%  |
| ❌     | WallTime | `test_color[graph0-3]`            | 31 µs   | 32.7 µs  | -5.16%  |
| ⚡     | WallTime | `test_multiprocessing_map[1000]`  | 66.4 ms | 60.9 ms  | +9.08%  |
| ⚡     | WallTime | `test_threadpool_map[10]`         | 2.5 ms  | 2.3 ms   | +5.54%  |
| ⚡     | WallTime | `test_sudoku[initial_grid0]`      | 8.3 µs  | 7.9 µs   | +4.81%  |

_…31 more changed benchmarks omitted_
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get_benchmark_result
Retrieve the full structured result of a single benchmark in a performance run: the instrument metrics (wall-time distribution, simulated time breakdown, or memory allocation breakdown), known issues, and whether a flamegraph is available.
Input
{
  "repository": "CodSpeedHQ/codspeed",
  "run_id": "6a315367cef14236ed18cd7b",
  "benchmark_name": "exec_harness::sleep 1",
  "runner_mode": "WallTime"
}
Output
{
  "name": "sleep 1",
  "uri": "exec_harness::sleep 1",
  "runnerMode": "WallTime",
  "flamegraphAvailable": true,
  "issues": { "callgraphGenerationFailure": null },
  "walltime": {
    "minSeconds": 1.001428826,
    "lowerFenceSeconds": 1.001428826,
    "q1Seconds": 1.0014400695,
    "medianSeconds": 1.001462736,
    "q3Seconds": 1.001541066,
    "upperFenceSeconds": 1.001572194,
    "maxSeconds": 1.001572194,
    "meanSeconds": 1.0014850014,
    "stdevSeconds": 0.00005703226150872855,
    "totalTimeSeconds": 5.007425007,
    "rounds": 5,
    "iqrOutlierRounds": 0,
    "stdevOutlierRounds": 0,
    "iterPerRound": 1,
    "warmupIters": 0
  }
}
​
query_flamegraph
Query and summarize a flame graph from a performance run. Returns hot spots (functions with highest self time), the call tree, and timing information for each function.
Input
{
  "repository": "CodSpeedHQ/codspeed",
  "run_id": "6a315367cef14236ed18cd7b",
  "benchmark_name": "crates/runner-shared/benches/memtrack_writer.rs::write_events[1000000]",
  "runner_mode": "Simulation"
}
Output
# Flame Graph Summary

---
benchmark_name: write_events[1000000]
runner_mode: Simulation
benchmark_total_time: 2.1 s
run_id: 6a315367cef14236ed18cd7b
truncated: yes
---

## Top 10 expensive functions (by self time)

| Function                                              | Origin     | Calls |         Self Time |        Total Time |
| ----------------------------------------------------- | ---------- | ----: | ----------------: | ----------------: |
| `ZSTD_compressBlock_fast_extDict_generic.constprop.0` | Unknown    |     2 | 468.5 ms (22.05%) | 572.8 ms (26.96%) |
| `Unknown symbol (0x188a80)`                           | Unknown    |    12 | 244.8 ms (11.52%) | 244.8 ms (11.52%) |
| `ZSTD_encodeSequences_bmi2`                           | Unknown    |     2 | 223.6 ms (10.52%) | 223.6 ms (10.52%) |
| `ZSTD_compressBlock_fast`                             | Unknown    |     4 | 213.3 ms (10.04%) | 213.3 ms (10.04%) |
| `ZSTD_compressStream`                                 | Unknown    |     2 |   97.9 ms (4.61%) |    1.3 s (60.07%) |
| `rmp::encode::str::write_str` (src/encode/str.rs)     | rmp@0.8.15 |     1 |   93.3 ms (4.39%) |   213 ms (10.03%) |

## Most expensive calls (by total time)

| Function                                                             | Origin          |       Self Time |     Total Time |
| -------------------------------------------------------------------- | --------------- | --------------: | -------------: |
| `runner_shared::artifacts::memtrack::MemtrackWriter<W>::write_event` | User code       | 32.5 ms (1.53%) | 2.1 s (99.80%) |
| `rmp_serde::encode::MaybeUnknownLengthCompound<W,C>::end`            | rmp-serde@1.3.1 | 18.3 ms (0.86%) | 1.6 s (77.23%) |
| `zstd::stream::zio::writer::Writer<W,D>::write`                      | zstd@0.13.3     | 30.8 ms (1.45%) | 1.4 s (64.57%) |

_…call tree, per-function details, and remaining hot spots omitted_

> Call tree filtered: showing up to 25 entries with ≥1.00% of root function
> total time. Re-query with `root_function_name` set to a function of interest
> for deeper exploration.

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Authentication

The CodSpeed MCP server uses OAuth for authentication. When you first connect, your MCP client will open a browser window where you log in to CodSpeed and authorize access. The client stores the resulting token and refreshes it automatically — no API keys to manage.
The MCP server has access to the same repositories and data as your CodSpeed account.