Run allowlisted test, build, or lint commands without a shell and return only exit code, failures, and the full log path to reduce context tokens.
Run an allowlisted test/build/lint command (no shell). Returns exit code + failures only; full log path included.
| Name | Required | Description | Default |
|---|---|---|---|
| cwd | No | ||
| command | Yes | e.g. "npx vitest run", "pytest -x" | |
| maxLines | No | default 80 | |
| timeoutSec | No |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose real behavior: allowlist enforcement, no shell expansion, truncated output (exit code + failures) with a full log path for the rest. It omits side effects of running builds, timeout behavior, and what a rejection looks like — meaningful gaps for an execution tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two tight sentences: the first front-loads what the tool does and its hard constraint, the second covers the return shape and log pointer. No filler, nothing repeated from the schema.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema or annotations exist, so the description is the sole source of behavioral context, and it covers output shape (exit code + failures, log path) well. It still leaves an agent guessing about timeout defaults, cwd semantics, and whether running a build has side effects.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 50%: `command` and `maxLines` are documented in-schema, while `cwd` and `timeoutSec` are not. The description adds genuine meaning for `command` (allowlisted, no shell), but says nothing that clarifies cwd scope or timeout units/limits, so it only partially compensates for the coverage gap.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb (run) and resource (allowlisted test/build/lint command) plus the key constraint (no shell). It implicitly separates itself from the read-only siblings (search, read_symbol, outline) by being the only execution tool, though it never names an alternative. Very close to a 5, but sibling differentiation is inferred rather than stated.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Allowlisted test/build/lint' and 'no shell' imply when the tool applies and what it will refuse, giving the agent usable boundaries. However, it never says when to prefer this over, say, search or read_symbol, nor what happens when a command is not on the allowlist. Usage is implied, not spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.