fs_read

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and description adds valuable context: returns sha256 of full file, shows truncated flag, rejects binaries while still returning sha256 for replace flows, and clarifies lease_id is optional. No contradiction.

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?

Three dense sentences, front-loaded purpose, no fluff; every sentence provides unique value (behavior, return, binary handling, read-only).

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 6 params, 0% schema descriptions, and presence of output schema, the description adequately explains purpose, constraints (project root, UTF-8), and key behavior (binary rejection, truncated content). Missing details: lease_id purpose, max_bytes interplay, and error conditions beyond binary, but overall sufficient for a read tool.

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%, but description compensates by clarifying line range for start_line/end_line, project root for project, and optional lease_id. However, lease_id and max_bytes are not fully explained, leaving some gap.

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?

Specific verb+resource: 'Read a UTF-8 text file under the project root' distinguishes from sibling fs_stat, fs_list, fs_search; mentions optional line range and return values that differentiate it as a content-reading 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?

Provides clear context (read-only, text files, under project root) and implicitly indicates when to use via 'read-only' and 'rejects binaries,' but does not explicitly name alternatives or when-not-to-use scenarios. The 'replace flows' mention hints at a workflow but lacks explicit exclusions.

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