files_read

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

No annotations are supplied, so the description carries the full disclosure burden and does so: 'Read-only; no side effects, auth, or rate limits.' It also documents batch failure semantics ('per-ID failures isolated, batch never partial-throws'), which is non-obvious behavior an agent needs before choosing a mode.

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?

Front-loads the core action, then packs modes, constraints, behavioral guarantees, and response shape into dense, well-ordered sentences with no filler. It is long but nearly every clause carries an operational constraint, so little could be cut without losing routing value.

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?

With no output schema provided, the description compensates by describing all three response shapes (single file object, partial-content object, and the {files, total_est_tokens, error_count, errors} batch envelope). For a 5-param, nested-object tool with no annotations, nothing needed to call it correctly appears to be 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, but the description adds constraints the JSON schema cannot express: exactly one of id/path/ids is required, section/lines are mutually exclusive, and both are valid only with id (not ids or path). It also clarifies the path must be the exact indexed absolute path, which sharpens a fuzzy parameter.

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+resource ('Read one or more files, in full or in part') and enumerates every mode with the exact parameter combination that triggers it. It also distinguishes itself from a sibling by naming files_describe as the inspect-without-cost alternative, so an agent can route correctly without opening another schema.

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?

Each mode is tied to a concrete condition (single-by-id, single-by-path, batch up to 200, partial-by-heading, partial-by-line-range), and it explicitly routes inspection-only work to files_describe. It stops short of addressing other close siblings like files_read_outline or files_regex_search, so the guidance is clear but not fully exhaustive.

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