read_file

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

With no annotations, the description carries full burden and does well: discloses size caps (1 MB/5 MB), byte-range semantics, and return-type mapping by MIME type. It does not cover auth or error behavior, but these are less critical for this read operation.

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?

Four tightly written sentences, front-loaded with the core purpose. Every sentence adds useful information (caps, ranges, return types) without repeating schema details.

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 no output schema and moderate complexity, the description covers purpose, limits, ranged reads, and return types. It omits error behavior and what happens when no range is given for a file over the absolute cap, but it is largely complete for a file download 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 covers 3 of 4 parameters (75%), and the description adds meaningful semantics: explains the cap values, clarifies rangeStart/rangeEnd for large files, and notes maxBytes works with rangeStart. This goes beyond the schema's raw metadata.

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?

Clear, specific verb+resource: 'Download a file and return its content inline.' The description further distinguishes from siblings like read_file_text and read_thumbnail by specifying mime-type-dependent return behavior (text, image, embedded resource).

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 concrete usage context: default/absolute caps and rangeStart/rangeEnd for large files. It implies when to use range parameters but does not explicitly name alternatives or exclusion conditions, so it misses the top tier.

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