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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds valuable behavioral detail: the 404 can indicate a wrong pairing rather than a missing topic, and it includes the default opt-in state. This goes beyond annotation coverage.

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?

Two sentences with no fluff. The first sentence front-loads the action and result; the second clarifies an important edge case. Every word 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 tool with two parameters and no output schema, the description covers the essential behaviors: what it returns (opt-in state) and the 404 semantics. It lacks nothing critical for correct invocation. A small gap is that it does not describe the response format, but since there is no output schema, that is not required.

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% for both parameters, so the description does not need to restate them. It adds relational context (topic must belong to section) but does not add parameter-level meaning beyond the schema. 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?

Description states a specific verb ('Get') and resource ('one subscription topic within a section'), plus the key payload ('default opt-in state'). It clearly distinguishes from sibling tools like get_preference_section and get_user_preference_topic by scoping to a section-topic pairing.

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 implies usage (fetch a single topic's details) but does not explicitly name alternatives or state when to prefer this over list_preference_topics or get_user_preference_topic. The 404 note gives context but not active routing guidance.

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