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

Annotations already establish this as read-only, idempotent, and non-destructive. The description adds useful behavioral detail beyond that: it returns every message in oldest-first order and explains the mention syntax format present in message bodies.

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 sentences with no filler. The first sentence establishes the core behavior and ordering, and the second provides essential content-format context, so every sentence earns its place.

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-only tool with two fully documented parameters, rich annotations, and an output schema, the description is complete. It covers what the tool returns, the ordering, and the special mention syntax the agent may need to interpret the response.

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?

The input schema already fully documents both parameters with descriptions and patterns, so the 100% schema coverage supports the baseline score. The description adds context about mention formatting but does not add new parameter-level meaning beyond the schema.

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 uses a specific verb ('Read'), identifies the exact resource ('one comment thread on an Artifact'), and specifies scope ('one thread'). It is clearly distinguishable from sibling tools like list_artifact_threads, create_artifact_thread, and reply_to_artifact_thread.

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 conveys this tool is for reading a single full thread, which implies the appropriate use case versus listing or modifying threads. However, it does not explicitly name alternatives or state when not to use the tool.

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