run_tests

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Since annotations are absent, description carries full burden. Discloses fixed argv, 120s timeout, 64KB cap, error for non-vitest runners, and return fields (runner, passed, exit_code, etc.). No contradictions.

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?

Single dense paragraph, efficient but could benefit from bullet points. Every sentence adds value. Not overly long.

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?

Handles complexity well: no output schema, but description lists all return fields. Covers safety constraints, parameter usage, and supported runner. Complete for a test execution tool.

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 has 100% coverage with descriptions. Description adds value by mapping filter to vitest --testNamePattern and clarifying path as in-tree file/directory. Good but schema already does heavy lifting.

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?

Clearly states it runs the vitest test suite with a safety envelope. Explicitly differentiates from other test runners (Pest/PHPUnit, pytest, Jest) by stating they return an error. Verb+resource+scope are specific.

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?

Provides clear context: vitest projects only, shell-exec pilot per council cut. Explains how to narrow runs with filter and path. Does not directly name alternative tools among siblings, but siblings lack test runners.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.