run_tests

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

No annotations are provided, so the description carries the full burden. It discloses that the result is a compact summary and that failure details require get_failures, which is genuine behavioral context. It omits side-effect information (spawning processes, writing coverage artifacts, the kill-on-timeout behavior) that an agent would want before invoking.

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 short, front-loaded sentences with no redundancy. The primary action comes first and the routing hint follows immediately; every clause earns its place.

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?

With no output schema, the description should convey what the compact summary contains and how options like coverage change it. It signals summarization and points to the drill-down tool, which covers the essential workflow, but leaves the shape of the returned summary unspecified.

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 description coverage is 100%, so all six parameters (projectDir, timeout, coverage, fileGlob, framework, testNamePattern) are already documented in the schema. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

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 and resource ('Run tests') plus the return character ('compact summary'), and explicitly names the sibling get_failures for drill-down. It does not differentiate from other run-oriented siblings like run_affected or rerun_failed, so it falls short of a 5.

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?

The second sentence gives useful follow-up routing ('Use get_failures to drill into failures'), which implies this tool is the entry point for a full run. However it never states when to choose this over run_affected, rerun_failed, or discover, nor any prerequisites such as a discovered project setup.

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