Test Coverage Report

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

With no annotations, the description carries the full burden. It does not say that this writes files to disk, whether existing coverage output is overwritten, roughly how long it takes, or that it requires a working phpunit setup — all material for an agent deciding whether to invoke a build-time command.

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 short sentence with no padding, and the key action is front-loaded. It is efficiently sized, though the brevity borders on under-specification rather than genuine conciseness.

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 values needn't be explained. But for a two-parameter tool with zero schema descriptions and zero annotations, the description omits parameter meaning and side effects (file writes), leaving the definition materially incomplete for correct invocation.

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 both parameters (format, output_dir) are undocumented in structured data. The description offers no detail on accepted format values or how output_dir is interpreted, only indirectly implying files are produced. It fails to compensate for the coverage gap.

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?

States a specific verb and resource ('generate a test coverage report') and names the underlying binary (vendor/bin/phpunit). However, it never distinguishes itself from the many sibling test tools such as test_run_phpunit or test_run_kernel, so an agent must infer that this is the coverage variant rather than a plain run.

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?

There is no when-to-use guidance, no mention of alternatives among the test_run_* / test_scaffold_* siblings, and no stated prerequisites (e.g., that PHPUnit must be installed). The agent is left to guess the selection conditions entirely.

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