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

Beyond the annotations (destructive, idempotent, not read-only), it discloses that the entire body is replaced wholesale, that the write is gated on the native source revision (an optimistic-concurrency guard), and that it doesn't start a chat turn or touch another home. That is real behavior an agent cannot get from the annotation flags alone.

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?

Two tight sentences, front-loaded with the action and the concurrency requirement, followed by the exclusions. Nothing redundant or padded.

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 destructive, five-required-parameter write with zero schema coverage, the description is too thin. It doesn't explain what expected_revision must match, what request_key is for (replay/idempotency), or what happens on revision mismatch — critical for a destructive call. An output schema exists, so return values need not be covered, but the input contract is under-explained.

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 0% and all five parameters are required, yet the description explains none of them. It only obliquely gestures at expected_revision via 'native source revision'; workspace_id, subject, body shape, and especially request_key are left entirely undocumented.

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: replace the writing subject's exact document body. The phrase 'writing subject' and 'native source revision' narrow it away from the generic document-edit siblings, and 'Does not run a chat turn' further disambiguates, though it never names the closest siblings like replace_studio_document_body.

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?

Conveys the operative condition (full-body replacement keyed to the native source revision) and one exclusion (no chat turn, no other home), which implies when to choose it. But it never names an alternative tool or states when to prefer a partial edit such as apply_studio_document_edits.

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