[adriencaccia]

This declares a Symposium plugin in the codspeed crate's [package.metadata.symposium]. With it, cargo agents gives coding agents the CodSpeed skills (from the skills/ directory of CodSpeedHQ/codspeed) and the CodSpeed MCP server. Projects depend on the compat crates, not on codspeed directly, so a symposium-dev/recommendations entry gated on those crates will point to this crate once it is released.

Tested with cargo-agents 0.5.1 and a local registry entry: both skills install, and Claude Code loads codspeed-setup-harness when asked to add a benchmark. Claude Code ignores the MCP entry until Symposium writes "type": "http" for it, which needs a fix on Symposium's side.

Refs COD-3968 (stays open until the recommendations entry lands)

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge.

Summary

Adds Symposium plugin metadata to codspeed:

• The CodSpeed package lists its skills and MCP server for Symposium.

No actionable issues were found. adriencaccia explicitly acknowledges that Claude Code ignores the MCP entry until Symposium emits "type": "http"; that upstream limitation is intentionally deferred.

_{Reviews (1) · Last reviewed commit: "feat(codspeed): declare a Symposium plug..." · Reviewed by Greptile}

[codspeed]

Merging this PR will regress 12 benchmarks

3 warnings, 1 note

⚠️ Unable to measure the execution of 59 benchmarks

These benchmarks measured no execution time, so their results are not comparable and count as unchanged. This usually happens when the compiler removes the code under test.

Prevent compiler optimizations

See affected benchmarks

⚠️ 17 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

⚠️ Base and head ran on different runner types

Some benchmarks with significant performance changes were compared across different runner types, so the changes might not come from the code. Run base and head on the same runner type, or use CodSpeed Macro Runners for more stable results.

Learn more about Macro Runners

Open the report in CodSpeed to investigate

ℹ️ 57 benchmarks have no flamegraph

• The flamegraph wasn't generated: most of the time was spent in runtime internals, which would leave nothing useful to analyze. (9 benchmarks)
• The flamegraph wasn't generated: no execution data was recorded while the benchmark ran. Make sure the compiler didn't optimize the benchmark out. (48 benchmarks)

See affected benchmarks

⚡ 12 improved benchmarks
❌ 12 regressed benchmarks
✅ 582 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	CPU Simulation	rem	178.1 ns	232.3 ns	-23.32%
❌	CPU Simulation	div	178.1 ns	232.3 ns	-23.32%
❌	CPU Simulation	find_highest_set_bit[42]	229.3 ns	283.5 ns	-19.11%
❌	CPU Simulation	find_highest_set_bit[1024]	229.3 ns	283.5 ns	-19.11%
❌	CPU Simulation	find_highest_set_bit[255]	229.3 ns	283.5 ns	-19.11%
❌	CPU Simulation	find_highest_set_bit[65535]	229.3 ns	283.5 ns	-19.11%
❌	Walltime	iter_batched_large_input	6 ns	7 ns	-14.29%
❌	CPU Simulation	spawn_on_parent_runtime	32.5 µs	37.4 µs	-13.2%
❌	Walltime	iter_batched_per_iteration	48 ns	52 ns	-7.69%
❌	CPU Simulation	iter_manual_simple	839.4 ns	893.5 ns	-6.06%
❌	Walltime	iter_with_setup	46 ns	48 ns	-4.17%
❌	Walltime	spawn_on_parent_runtime	24.7 µs	25.7 µs	-3.7%
⚡	Walltime	mut_borrow	17 ns	7 ns	×2.4
⚡	Walltime	hamiltonian_cycle[5]	1,289 ns	923 ns	+39.65%
⚡	Walltime	hamiltonian_cycle[6]	1,265 ns	962 ns	+31.5%
⚡	Walltime	graph_coloring[5]	1.4 µs	1.1 µs	+30.39%
⚡	CPU Simulation	add_two_integers[(42, 13)]	288 ns	233.8 ns	+23.17%
⚡	CPU Simulation	add_two_integers[(255, 255)]	288 ns	233.8 ns	+23.17%
⚡	Walltime	iter_batched_ref_large_input	6 ns	5 ns	+20%
⚡	CPU Simulation	add_two_integers[(1024, -1024)]	349.4 ns	295.2 ns	+18.35%
...	...	...	...	...	...

ℹ️ Only the first 20 benchmarks are displayed. Go to the app to view all benchmarks.

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing cod-3968-ship-codspeed-skills-and-mcp-to-symposium-cargo-agents-users (28908bc) with main (fce04a6)}