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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so that needs no restating. The description adds value beyond them by disclosing the return shape ('as text and its link') and the error behavior for an unknown id, which annotations cannot express.

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 short sentences with no filler: identity/lookup key first, then return value, then failure mode. 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?

There is no output schema, so the description must describe the return value — and it does (text plus site link), along with the error case. For a single-parameter read tool with full annotation coverage, nothing an agent needs is missing.

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 single parameter is documented there, including its origin ('catalog id returned by find_assistant'). The description only restates 'by id', so baseline 3 is appropriate — the schema carries the semantic load.

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 and resource ('Retrieve the public AutoMessage assistant catalog entry') and scopes it to lookup 'by id', which cleanly separates it from the sibling find_assistant (search vs. fetch-by-id). An agent can tell which tool to call without opening either schema.

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 lookup condition is clear (you must have an id) and the schema ties that id back to find_assistant, effectively routing the agent through the sibling first. However, the description itself does not explicitly say 'use find_assistant to obtain an id' nor state any when-not condition, so it stops short of full routing guidance.

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