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

Annotations already declare destructiveHint, openWorldHint, and non-idempotent. The description adds a meaningful behavioral fact not in annotations: 'people following the work order may be notified', surfacing a side effect the agent should anticipate. It doesn't cover irreversibility or failure modes, keeping it from a 5.

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?

A single tight sentence plus endpoint, with the WRITE mutation type front-loaded. No wasted words.

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 2-required-param mutation with full schema coverage and rich annotations, the description covers action, side effect, and endpoint adequately. No output schema exists, so return-value explanation isn't expected; error/permission behavior is the only minor gap.

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 description coverage is 100%, so both parameters (work_order_id, text) are well documented in the schema. The description adds no syntax or format meaning beyond the endpoint path implying the id, so baseline 3 applies.

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?

States a specific verb (post a message/comment) and resource (work order activity thread), and the endpoint POST /work-orders/{id}/update-messages nails the scope. It's clearly distinguishable from siblings like upkeep_update_work_order or upkeep_create_work_order, which mutate fields rather than append a comment.

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 'WRITE:' prefix signals this is a mutation, and 'post a message on a work order's activity thread' implies the use case. However, it never states when to use this vs alternatives or any prerequisites (e.g., must the work order exist/be open), leaving guidance implicit.

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