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

Although annotations already mark the tool as read-only, idempotent, and non-destructive, the description adds meaningful behavioral details: it returns at most 100 entries, newest last, in reading order, and explains protocol/endpoint context. It also clarifies the kind filtering behavior and the note/discussion alias. This goes well beyond what the annotations provide.

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 compact and information-dense: it covers the action, resource, content type, limit, ordering, filtering, read semantics, and the relevant sibling in two sentences. It is front-loaded with the core purpose and every clause contributes useful information without redundancy.

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 read tool with rich annotations and fully documented parameters, the description is complete: it identifies required task_id, optional kinds, response contents, ordering, limit, and read-tier safety. It even names the sibling for writes. With no output schema required, the agent has enough context to call this tool correctly.

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%, and the schema already explains both task_id and kinds, including the comma-separated filter and the note/discussion alias. The description reinforces these meanings but does not add significant new parameter-level information beyond what the schema provides, so the baseline of 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 opens with a specific verb and resource: 'Read a task's trail messages.' It then specifies the message kinds, ordering, and limit, and explicitly contrasts itself with tascan_post_message via the 'Read tier' note. This makes the tool's purpose unmistakable and distinct from both posting and other task-read tools like tascan_get_task.

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 clearly states the tool is for reading (when to use it) and explicitly routes write operations to tascan_post_message ('Post with tascan_post_message'). It also explains when the optional kinds filter is relevant. This gives the agent explicit context for choosing this tool over its direct sibling.

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