run_failed

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

Despite no annotations, the description fully discloses the tool's behavior: it runs only last-failed tests, explains framework-specific mechanisms (pytest --lf, Jest --onlyFailures, etc.), and states the return shape matches run_tests. 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?

The description is moderately long but well-structured: it starts with the core purpose, then lists framework-specific details, and finishes with return shape and prerequisites. Every sentence adds value, though slightly verbose; could be trimmed slightly without loss.

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?

Given the tool's complexity (supporting multiple test frameworks) and lack of output schema, the description is comprehensive. It covers usage context, prerequisites, behavior per framework, and return shape, making the tool usable without additional context.

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?

There are zero parameters, and schema coverage is 100% vacuously. Following the guideline '0 params = baseline 4', the score is set to 4. The description does not add parameter information because none exists, but it compensates by explaining the tool's behavior and prerequisites.

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?

The description clearly states it reruns only the previously failed tests, using specific verbs like '只重跑' and contrasting with the full suite. It differentiates from sibling tool 'run_tests' by specifying the target as only failed tests.

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?

Explicitly says when to use ('適合修完一個 bug 後驗證迭代') and notes the prerequisite that a prior run_tests must have been executed. It also mentions the tool is faster than running the full suite, guiding the agent to use it for efficient iteration.

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