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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond them: it confirms reading does not mark messages sent or mutate the conversation, states the return content, and flags the Cotlet API key authorization requirement.

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?

Three compact sentences, front-loaded with the core purpose and scope, then output shape, then the read-only assurance and auth note. Every sentence carries information; nothing is wasted.

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 two-parameter read tool with no output schema, the description covers return content ('text messages with sender and time'), ordering ('newest first'), non-mutation, and auth. Pagination behavior is not mentioned, but the limit default is in the schema, so coverage is nearly complete.

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 both client_id ('Client ID from list_clients') and limit ('Default: 30') documented in the schema itself. The description adds only the indirect hint that a client scopes the conversation, so the 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 gives a specific verb and resource (list recent messages) plus scope ('in your conversation with a client, newest first') and output shape ('text messages with sender and time'). It is clearly the read counterpart to truecoach_send_message, though it never names that sibling explicitly, which keeps it just short of a 5.

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?

Usage is implied by the phrase 'in your conversation with a client' and by the note that reading doesn't send anything, which steers an agent away from send_message. However, there is no explicit when-to-use or when-not-to-use guidance and no named alternative, so it lands at minimum-viable.

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