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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely new behavior: a 512 KB size cap, that binary files are described rather than returned, and the shared-hosting web root boundary — all useful for an agent predicting output.

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 tightly packed sentences, front-loaded with what is returned and its scope, followed by the workflow rule and edge-case handling. No filler.

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?

For a two-parameter read tool with no output schema, the description supplies return type, size limit, and binary-file behavior, which is nearly everything needed to call it. Missing only error/not-found behavior and permission prerequisites.

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 both 'domain' and 'path' are already documented in the schema, including the relative-to-web-root convention. The description adds only marginal meaning ('one file', implicitly scoped to the customer's site), so baseline 3 applies.

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 and resource ('Returns the text of one file') and scopes it precisely to a customer's shared hosting site's web root, listing file types. This clearly distinguishes it from list_site_files (enumeration) and write_site_files (mutation) among the siblings.

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?

Explicitly instructs to ALWAYS read before changing with write_site_files and to change only what the customer asked for, which ties it to a concrete workflow. It does not state when NOT to use it (e.g. use list_site_files to discover paths first), so it falls short of full alternative routing.

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