files_index

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

Since no annotations are provided, the description carries the full burden. It discloses that retrieval is cheap-first, returns file-level summaries, and excludes leaf content. While it doesn't detail the exact summary format, it provides sufficient behavioral transparency for a triage tool.

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?

The description is three concise sentences, front-loaded with the primary purpose. Every sentence adds value: purpose, behavior, and usage guidance. No wasted words.

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?

Given the 9 parameters and no output schema, the description is moderately complete. It explains the use case and relationship to siblings but lacks parameter guidance and output format details, leaving gaps for an agent to navigate.

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?

With 0% schema description coverage and 9 parameters, the description fails to explain any parameters beyond general purpose. The agent receives no guidance on limit, corpus, directory, or other filtering options, leaving a significant gap in parameter understanding.

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 clearly states what the tool does: 'Return file-level summaries for triage'. It distinguishes itself from sibling tool files_search by specifying 'cheap-first retrieval -- no leaf content' and explicitly advises using this tool before files_search to decide which files to deep-read.

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 provides explicit usage guidance: 'Use BEFORE files_search' and explains the tool's purpose in the triage workflow. It implies when not to use (when leaf content is needed, use files_search), giving clear context and alternatives.

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