Delimit Test Coverage

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, lowering the bar. The description adds genuinely useful context beyond that: gated by require_premium (a key failure mode), experimental status, and the heuristic nature of coverage-runner detection. The 'Side effects: read-only inspection' line is redundant with the annotation, but the premium gating and reliability caveat earn the score.

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?

Well-organized with labeled sections (when to use, when not to use, sibling contrast, side effects), front-loaded with the core function in the first sentence. Each section earns its place; the experimental and premium-gating disclosures justify the length. Only minor redundancy is the read-only line repeating the annotation.

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?

Complete for a 2-parameter tool with an output schema and safety annotations. Covers purpose, selection criteria, exclusions, sibling alternatives, side effects, premium gating, backend call, and an experimental/heuristic caveat. The output schema covers return values, so the description needn't explain them.

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 both parameters (project_path, threshold) are already documented with descriptions and the threshold has a default. The description mentions 'against a threshold' and pass/fail semantics, echoing the schema rather than adding new parameter-level detail. Baseline 3 is correct when the schema carries the full weight.

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?

Opens with a specific verb+resource ('Analyze test coverage for a project') and then sharpens the scope: surfaces coverage by file/folder against a threshold and produces a pass/fail signal for CI. The sibling contrast explicitly distinguishes it from delimit_test_smoke and delimit_test_generate, so an agent can tell them apart without opening schemas.

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 explicit 'When to use' and 'When NOT to use' sections with named alternatives (delimit_test_generate for stubs, delimit_test_smoke for smoke runs), plus a sibling-contrast paragraph explaining exactly how each sibling differs. Nothing is left to inference.

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