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

The annotations already mark this as a non-read-only mutation, but the description adds meaningful context: persistence across sessions, re-injection on the next voice session mint, current-call application, and the write-tier approval workflow. It also clarifies the success signal ('the card is the yes'), which is not in the annotations.

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 front-loaded with the core behavior and use cases, then delivers policy details in a compact second paragraph. The bracket section is dense but every clause adds operational guidance, so nothing is wasted.

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 write tool with no output schema, it covers persistence, scope, approval requirements, timing, and expected response in enough detail to call it correctly. It doesn't explicitly address error/denied-approval behavior, but that is a minor gap given the schema and annotations.

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?

With 100% schema description coverage, each parameter is already documented, including a concrete example for 'note'. The tool description contributes domain context but does not need to repeat parameter formats; it adds little 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 opening phrase 'Append one durable speech/taste preference for THIS operator only' names a concrete verb, resource, and scope. It also differentiates itself from the shared FreedomOS CoS template and from set_cos_preferences by emphasizing 'append' and 'this operator only.'

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?

It spells out explicit triggers ('hard to follow', 'how cards should sound', 'remember I prefer…') and tells the agent to act on the first clear ask without re-asking. It establishes boundaries ('does not edit the shared FreedomOS CoS template') but does not name sibling alternatives such as set_cos_preferences or append_cos_lesson.

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