coverage_report

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false, destructiveHint=false), so the burden is lower. The description nonetheless adds real behavioral context: results come 'from the latest run' (temporal scope), MC/DC is conditional on C/C++ with clang >= 18 (capability gating), and it includes code no linked test executes (untested-code reporting).

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?

A single dense sentence that front-loads the core coverage types before qualifications. No filler, though the clause stacking makes it slightly heavy to parse.

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?

An output schema exists, so return-value shape needn't be explained, and coverage content is well described. The gap is the sole input parameter and when to choose this tool over siblings, leaving an agent unsure how to scope the call.

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 0% for the single req_id parameter, so the description carries the compensation burden and does not meet it. It never mentions req_id, its optionality, or whether omitting it reports all requirements versus a single one.

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 names a specific resource (coverage of each requirement's implementing code) and enumerates its contents: statement/branch coverage, MC/DC, uncovered lines/branches/conditions, and untested implementing code. This is clearly distinguishable from siblings like evidence_report or trace_matrix. It never explicitly contrasts itself with an alternative, which keeps it out of 5 territory.

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?

No when-to-use, when-not-to-use, or alternative tools are mentioned. The agent must infer that this is the coverage-metric tool from the content alone, without routing guidance among the eleven siblings.

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