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

Annotations already flag destructiveHint=true and non-idempotency, but the description adds substantial context the annotations cannot carry: the required content:write scope, a mandatory two-phase confirm flow, the fact that the first call is a no-op dry run, that unknown fields are refused by name, and that the first call returns a summary plus confirm_token.

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 definition is short and front-loaded, putting the action and required scope first and the two-call protocol immediately after. The clipped phrasing ('Two calls.') is efficient, though slightly telegraphic compared to a fully written-out procedure.

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 two-parameter mutation tool with no output schema, the description covers permissions, sequencing, dry-run semantics, failure behavior for unknown fields, and the human-approval gate. An agent has everything needed to invoke it correctly without guessing.

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 schema documents confirm_token but leaves id undescribed, so coverage is only 50%. The description compensates by explaining exactly when confirm_token must be omitted versus supplied and that it must reuse the prior results, and by clarifying that fields the tool does not take are rejected by name despite additionalProperties being true.

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 opens with a specific verb+resource ('Change a mix'), which pairs cleanly against siblings like create_mix, delete_mix, and get_mix. It does not explicitly name those alternatives, so the differentiation is implied by the verb rather than stated.

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 gives a clear when-to-use context (modifying an existing mix) and an explicit procedure: first call without confirm_token, show summary to the person, second call only after agreement. It stops short of naming alternative tools such as reorder_mixes for ordering-only changes.

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