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

Beyond annotations, the description discloses that the team is notified by email, the message is sent in the person's name, test cases are refused, there is a rate limit of 20 per 10 minutes per organization, and the call returns the message as stored. It also specifies the authentication requirement. These are meaningful behavioral details not present in the structured 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 front-loaded with the primary usage instruction and keeps each sentence focused on a distinct fact. It is somewhat longer than strictly necessary, but no sentence is wasted and the structure remains easy to scan.

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 write operation with no output schema, the description covers the return value, authentication, rate limits, refusal behavior, and the relevant alternative tool. It provides everything an agent needs to invoke the tool correctly without relying on additional structured fields.

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 input schema already fully documents both parameters with patterns and semantic descriptions. The description repeats 'Input: the case id and body' and emphasizes 'Send only what the person asked to say', but adds no new syntax or format constraints beyond what the schema provides. A baseline of 3 is appropriate when the schema does the heavy lifting.

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 states a specific verb and resource: 'Sends the team a message about a live case'. It explicitly distinguishes this from the sibling tool for editing drafts by naming 'evictions_update_case'. An agent can tell exactly what this tool does and when it applies.

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 gives explicit when-to-use guidance ('Use this when the person asks you to write to the Evictions API team about one of their live cases') and when-not-to-use guidance ('Do not use this to change a draft (use evictions_update_case)'). It also states prerequisites (sign-in or API key) and operational limits (20 per 10 minutes, test cases refused).

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