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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds value by listing the returned fields (subject, body, sender, recipient, schedule), which goes beyond what annotations provide. It doesn't describe any side effects, but for a read-only operation with no output schema, this is adequate and does not contradict the 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?

The description is a single, front-loaded sentence that immediately states the tool's purpose, lists the returned fields, and provides the ID source. There is zero redundancy or fluff; every clause contributes useful information. It is efficiently structured for an agent to parse quickly.

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 tool's simplicity (one integer parameter, no output schema) and the annotations covering read-only behavior, the description provides the essential context: what is returned and where to obtain the ID. It does not mention response format or pagination, but those are not necessary for a single-object retrieval. The description is sufficiently complete for correct invocation.

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 schema has a single integer parameter 'id' with no description, and schema coverage is 0%. The description compensates by indicating that IDs come from hires_list_candidate_messages, which gives the agent a source for the value. However, it does not explicitly explain that the ID represents a notification message identifier or its format. The guidance is helpful but not fully complete, so a 3 is appropriate.

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 it retrieves a notification email and enumerates the specific fields returned (subject, body, sender, recipient, schedule). It also explicitly references the source of IDs (hires_list_candidate_messages), which distinguishes this tool from other 'get' tools like hires_get_message or hires_get_application. The verb 'Get' plus the resource 'notification email' and the detail make the purpose 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?

The description provides a clear usage signal by stating that IDs come from hires_list_candidate_messages, which tells the agent exactly where to obtain the required input. While it doesn't explicitly mention alternatives or when not to use this tool, the reference to the list function implies the proper workflow. This is sufficient guidance for a simple retrieval tool.

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