Warm

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does this thoroughly: no content/previews/paths returned, counts-only output, token cost, failure reason categories, and truncated/incomplete behavior when a cap stops the walk. This is unusually transparent about side effects and 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?

Though longer than average, every sentence earns its place: core purpose, cost, output restrictions, failure semantics, and usage workflow. The structure is front-loaded with the essential definition and uses clear paragraphing and lists of error reasons, making it scannable for an agent.

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?

Despite having no output schema, the description fully compensates by explaining what the agent will get back: counts of indexed/current/not-indexed files, skipped counts, failure reasons, and truncated/incomplete flags. Combined with the complete input schema and usage guidance, nothing necessary for correct invocation is missing.

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%, so the baseline is 3. The description adds meaning beyond the schema by explaining the significance of max_files behavior ('If a cap stopped the walk early you get `truncated` or `incomplete`') and listing concrete failure reasons such as `not_found`, `not_a_file`, `binary`, and `too_large` that map to path-related outcomes. This enriches the parameter semantics beyond the schema's basic descriptions.

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 first sentence states a specific verb and resource: 'Index files into the cache so `grep` and `search` can see them, returning counts only.' This clearly distinguishes warm from read, search, grep, and other siblings by positioning it as a cache-warming pre-step rather than a retrieval or content tool.

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 final paragraph explicitly tells the agent when and how to use the tool: 'Use it before searching an unfamiliar tree, then `grep` for the exact string or `search` for the concept, and `read` only what those name.' This gives concrete workflow context and names the related sibling tools, satisfying the when-to-use and alternatives requirement.

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