list_keys

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

No annotations exist, so the description carries the full burden. It usefully discloses that output is flattened keys and that the operation is local-only with no translation API calls, but says nothing about the return shape (array of key strings?) or error behavior for malformed/nonexistent files.

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 short sentences, zero waste, with the core purpose front-loaded and the constraint immediately following. Nothing could be removed without losing signal.

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 single-parameter read tool this is nearly sufficient: purpose, input domain, and a key constraint are all covered. With no output schema present, a brief note on what the returned key list looks like would close the last gap.

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 coverage is 100% and the sole filePath parameter is already documented as 'Path to locale JSON/YAML.' The description reinforces that only one file is involved, adding marginal meaning beyond the schema, which sets the baseline at 3.

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 ('List') and resource ('flattened keys') scoped to 'a single locale file,' which implicitly separates it from compare_locales (two files) and find_empty_translations (filtered subset). It stops short of naming those siblings explicitly, but the scope is unambiguous.

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 gives a hard boundary — 'Local locale JSON/YAML files only — does not call translation APIs' — which is useful exclusion guidance. However, it never states when to reach for this tool versus compare_locales or find_empty_translations, leaving that routing to inference.

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