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

Annotations already provide readOnlyHint=true and destructiveHint=false, so the read-only nature is covered. The description adds that the preferences are 'saved' and 'user-scoped', clarifying what was previously stored for this operator. It does not detail return format or pagination, but annotations cover the safety profile, so this is acceptable.

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, no filler. The first sentence states the operation and scope; the second gives the intended use case. Every word contributes.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description covers the operation, scope, and usage context. Annotations add read-only and idempotent hints. The only minor gap is no explicit mention of what happens if companyId is omitted, but the schema already documents it, and the tool is user-scoped so the parameter is not central.

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 has only one optional parameter, companyId, and its description is provided inline ('FreedomOS company id to act within'). Schema description coverage is 100%, so the tool description need not repeat parameter details. It does not mention parameter semantics beyond the schema, which matches the baseline of 3.

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 begins with 'Read THIS operator's saved CoS speech/taste preferences', stating a specific verb and resource and scoping to the current operator. It distinguishes from siblings like set_cos_preferences or append_cos_preference, and the user-scoping clarifies it is not fetching global preferences.

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 second sentence explicitly says 'Use when confirming what you will remember about how they like cards and talk,' giving a clear when-to-use scenario. It does not mention alternatives or exclusion criteria, but the context is sufficient for the agent to select it.

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