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

Annotations only declare readOnlyHint=false and destructiveHint=false, so the description adds significant value: it discloses that only sent fields are changed (partial update), that confirmation is mandatory, and that prompt updates are refused with CONFLICT when the case uses a library prompt. No contradiction with annotations.

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 sentences, each dense with information. The core purpose is front-loaded, followed by usage instructions and conflict handling. No filler 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?

The description covers the essential workflow (read first, confirm, update), the conflict scenario, and the partial update behavior. Given the tool's complexity (10 params, write operation), this is quite complete. It doesn't mention idempotency key usage or other error cases, but an output schema exists, reducing the need to explain return values.

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 only 20%, so the description compensates by clarifying partial update semantics (only fields sent are changed) and the special behavior of the prompt parameter (CONFLICT with systemPromptId). It also ties the 'confirmed' parameter to the explicit confirmation step. However, it doesn't address other optional parameters like tags, title, or variables beyond what the schema's types imply.

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 the verb 'Update' and the resource 'case', and specifies the required workflow of showing proposed changes and confirming. It distinguishes itself from sibling tools like update_contact by targeting 'case' and referencing get_case as a prerequisite.

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 explicitly instructs to 'Read it with get_case first', clarifying the sequence of operations. It also specifies when to use (after user confirmation) and when not to (when systemPromptId exists, report CONFLICT rather than retrying), which is a clear exclusion.

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