Coverage gaps in changes

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

With no annotations, the description carries the full burden of behavioral disclosure, yet it only names the intersection logic. It does not clarify whether the tool requires a git repo, reads files from disk, mutates anything, or what it returns in edge cases.

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 sentences with no filler; the core operation is front-loaded and the usage context follows. 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?

For a 5-parameter tool with no annotations and no output schema, this definition is too sparse. An agent can guess the intent but not confidently configure cwd, base, mode, or workspace, nor anticipate failure or output shape.

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%, so the description must explain the five parameters. It indirectly implies reportPath refers to LCOV and base/workspace relate to git changes, but mode, cwd, and workspace semantics are left entirely uninferred.

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 concrete operation — intersecting git-changed lines with uncovered lines from Istanbul/LCOV — and a clear resource. This distinguishes it from siblings like get_coverage or analyze_changes, which address coverage or change analysis separately.

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?

"Use this before generating tests" explicitly states when to invoke the tool. It does not mention alternatives or exclusions, but the timing guidance is unambiguous enough to route an agent correctly.

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