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

The description discloses partial update behavior (only supplied fields changed), the OUT_OF_SYNC rejection with nothing written, and the need to copy updatedAt from a fresh read. This adds significant value beyond the annotations, which only indicate idempotent and non-destructive properties.

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 three sentences, each with a distinct purpose: core operation, prerequisite step, and critical requirement. It is front-loaded with the action and scoping, with no redundant or vague language.

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 empty input schema, the description covers all essential invocation details: confirming existence via search/get, providing current updatedAt, and the error behavior on conflict. The output schema exists, so return format is not needed. It is complete for a partial-update tool with concurrency control.

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?

Even though the schema declares no parameters, the description provides the essential semantics: 'by id' implies an id parameter, and 'REQUIRES baseUpdatedAt' names the exact parameter and its provenance. This compensates for the empty schema and gives the agent enough to invoke correctly.

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 action (patch), the resource (user-authored rule), and the scoping (by id). It distinguishes this from create/delete operations by focusing on existing rules, making it unambiguous.

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?

It explicitly instructs to use vault_search_rules / vault_get_rule first to confirm the id and current state, and explains the baseUpdatedAt requirement for conflict handling. It does not explicitly name alternatives, but the precondition is clear.

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