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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds context about the content (messages and support answers) and the intended workflow, but does not disclose additional behaviors like return format or rate limits. With annotations carrying the safety burden, this is adequate but not rich.

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 two short, front-loaded sentences. The first states what the tool returns, and the second gives the usage context. No wasted words; every sentence contributes to the agent's understanding.

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 read tool with one parameter and no output schema, the description tells the agent what it returns, when to use it, and indirectly how to get the parameter (via schema). It is complete enough for the agent to invoke it correctly, though it doesn't elaborate on the exact response structure.

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%, with the parameter description explicitly stating 'The UUID of the support thread: call list_support_threads to find it.' The main description adds no additional information about the parameter, so it does not go beyond what the schema already provides. Baseline 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 states the tool returns 'One support thread with its messages, including the answers of the support team,' which clearly identifies the resource and action. It also ties to a specific workflow with 'after contact_support,' distinguishing it from list_support_threads which lists threads rather than reading a single one.

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 says to use it 'after contact_support to relay the answer to the user,' providing a clear trigger and purpose. It does not explicitly mention alternatives or when not to use it, but the phrase 'after contact_support' implies a sequencing that effectively guides usage.

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