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

Annotations only include idempotentHint: false, which already indicates non-idempotence. The description adds that it returns only a confirmation (uuid, title, modified state) rather than the entire Riddle, which is useful. However, it does not elaborate on other behavioral aspects like side effects or permissions, but given the simplicity, this is sufficient. It neither contradicts annotations nor adds substantial extra context beyond return behavior.

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 a single, well-structured sentence that front-loads the action and includes a clear note about the return value. There is no redundant information, and every phrase is necessary. It is concise and immediately informative.

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 simple mutation tool with two clearly documented parameters and no output schema, the description provides sufficient context: it states the action, the target, and the nature of the response. It does not address error cases or prerequisites, but these are not essential for this level of complexity. The description covers all that an agent needs to invoke the tool correctly.

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?

The input schema has 100% description coverage, with both UUID and title well-documented. The description reinforces the meaning ('specified UUID' and 'new title') but does not add extra semantic detail such as format constraints or examples. Since the schema already explains the parameters clearly, the description provides no additional value beyond confirmation, justifying a baseline score of 3.

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 ('Renames a Riddle'), the specific resource ('with the specified UUID'), and distinguishes it from siblings by noting it only returns a confirmation rather than the full Riddle. The verb and resource are explicit, and it differentiates from riddle_get and riddle_delete by focusing on the rename operation.

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 provides clear context for when to use this tool (renaming a Riddle). It does not explicitly mention alternatives or when not to use it, but for a simple rename operation, the purpose is self-evident. Given the sibling tools include other mutation operations like riddle_delete, the description's focus on 'renames' and 'confirmation' makes its intended use clear without needing exclusions.

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