run_failed

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

With no annotations provided, the description carries full behavioral burden. It details framework-specific implementations (pytest --lf, Jest --onlyFailures, etc.) and mentions output shape matches run_tests. Missing edge case behavior (e.g., no failed tests) and error conditions.

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 comprehensive but dense; every sentence provides value. It front-loads the main purpose, then lists framework specifics, prerequisite, and output format. Slightly verbose but efficient.

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?

Despite no output schema or annotations, the description covers purpose, usage, behavior, and output format. Missing edge cases (no failures, errors) and potential side effects, but sufficient for a simple 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?

Input schema has zero parameters, and description explains why no parameters are needed (it uses last failed state from prior run). This adds meaning beyond the schema, which already has 100% coverage.

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 failed tests from the last run, emphasizing speed advantage over full suite. It distinguishes itself from run_tests by specifying the last-failed logic across multiple frameworks.

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 description explicitly notes the prerequisite of a prior run_tests execution, gives context for iterative bug-fixing, and implies when not to use (if no prior run). It could be stronger with explicit exclusion criteria.

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