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

Annotations already declare this as a non-read-only, destructive mutation, and the description adds genuine context beyond them: partial-update semantics ("Only the fields you provide change") and an authorization requirement ("Owner-only"). It doesn't describe failure modes or response shape, but these additions exceed what the annotations provide.

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 short, front-loaded sentences with no filler; the identity of the tool comes first, followed by the mutation contract, the permission gate, and the sibling routing. Every sentence earns its place.

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 6-parameter mutation with full schema coverage but no output schema, the description covers what changes, who may call it, and where adjacent data is edited elsewhere. Missing only return behavior and error conditions, which are minor given the schema and annotations cover the rest.

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 100%, so the baseline is 3; however the description adds real meaning the schema lacks by stating that only supplied fields are modified, clarifying that omitted optional fields are preserved rather than cleared. That partial-update contract is not derivable from the schema alone.

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+resource ("Update a project's own details"), and the phrase "own details" signals it operates on the project entity itself rather than its children. It partially differentiates from a sibling by routing instruction documents to update_instruction, though it doesn't distinguish from update_batch/update_work/etc. Clear but not fully sibling-aware.

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?

"Owner-only" gives a permission precondition and "Only the fields you provide change" implies patch semantics, and it names update_instruction as the route for instruction docs. However there is no guidance on when to choose update_project over archive_project/delete_project or when it should not be used. Implied but not explicit usage guidance.

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