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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description adds genuinely new behavior: partial update semantics ('only what you pass changes') and, critically, the temporal scoping rule that only FUTURE deals use new terms while booked deals keep their numbers. That forward-only effect is exactly the kind of consequence an agent must know before mutating a plan. It does not cover permissions or error behavior.

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?

Four short sentences, prerequisite front-loaded in parentheses, then purpose, then the most consequential behavior (future-only effect), then a one-line clarification. No filler; every sentence carries information.

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 an 11-parameter mutation tool with full schema coverage and no output schema, the description covers the prerequisite, partial-update behavior, and downstream effect on deals. The reliance on 'same fields as create_plan' means an agent must cross-reference another tool for field meaning, a minor but real gap.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema: partial-update semantics ('only what you pass changes') and a pointer to create_plan for field definitions. The 'remove_cap true = no cap' line largely restates the schema's own description, so it adds little.

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 ('Change') and resource ('an existing commission plan') and explicitly contrasts with create_plan by noting it takes the same fields. An agent can distinguish this from create_plan and archive_plan without opening schemas, though the 'same fields as create_plan' phrasing defers some meaning to a sibling.

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?

Gives a clear prerequisite ('Needs the workspace_key from create_workspace') and implies use for modifying rather than creating plans. It does not explicitly say when to use archive_plan instead, nor what happens if a field is omitted beyond the partial-update note.

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