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

The description adds significant behavioral context beyond annotations: it specifies the file size cap (5242880 bytes), the failure mode (FILE_TOO_LARGE rather than truncation to avoid corruption), and the workflow dependency on get_site.filePaths. Annotations already indicate readOnlyHint=true, idempotentHint=true, destructiveHint=false, and the description aligns with these, adding useful constraints.

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 four sentences with a clear front-loaded purpose: 'Return the bytes of one file currently served by the site.' Each sentence adds value: usage workflow, size limit, and discovery method. No unnecessary words or redundancy.

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 tool has 4 parameters (1 required), 100% schema coverage, and an output schema (not shown but present), the description covers the essential context: return type (bytes), usage pattern, size limitations, and path discovery. It is complete enough for an agent to select and invoke correctly without additional clarification.

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 description coverage is 100%, so baseline is 3. The description does not detail individual parameters beyond what the schema provides, but it adds workflow context (e.g., 'use list of paths from get_site.filePaths' for the path param) and clarifies the maxBytes behavior. This is adequate but not exceptional.

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 'Return the bytes of one file currently served by the site.', identifying the verb 'return' and resource 'bytes of one file'. It distinguishes from sibling tools like read_files (plural) and read_source_file by emphasizing 'one file' and the deployment context, and it references get_site.filePaths for discovery.

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 a concrete use case: 'inspect or edit existing content (call read_file → modify → update_site mode:''patch'')' and explains the iterative workflow benefit. It also notes when not to use (for files larger than 5242880 bytes) and recommends using get_site.filePaths for discovery. However, it does not explicitly contrast with other read-related siblings like read_source_file.

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