cos_doc_headers_by

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds context that the scan is 'header-only' and 'frontmatter' filtered, which is useful. However, it does not disclose behaviors like default limit handling, ordering, or whether frontmatter filters combine via AND/OR, leaving some gaps beyond the annotations.

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 a single compact sentence with no filler or redundancy. It is front-loaded with the key action ('Bulk header-only scan') and gives the filtering context. It is slightly telegraphic, but for a short description it is appropriately concise.

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?

The description leaves significant gaps for a tool with six optional parameters and zero schema coverage. Although annotations cover safety and an output schema exists, the lack of parameter guidance makes it hard to know how to construct a correct filtered scan. The description is too minimal to be considered complete 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 coverage is 0% for six parameters, yet the description only mentions the high-level idea of frontmatter filtering. It does not explain how root, ssot, layer, limit, domain, or since_iso map to filtering behavior or how they should be used, so the description does not compensate for the missing schema 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 description states a specific action—bulk header-only scan—on doc headers with frontmatter filtering, making the core purpose clear. It is not tautological and the title reinforces 'List Doc Headers by Frontmatter Filter.' It lacks explicit sibling differentiation, but 'bulk header-only' helps distinguish from singular or search tools like cos_doc_header and cos_doc_search.

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 implies usage when a bulk, header-only scan of documents filtered by frontmatter is needed. It does not explicitly state when to prefer alternatives or when not to use this tool, so no exclusions or alternative guidance are provided.

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