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

Beyond the annotations (readOnly=false, idempotent=true, destructive=false), the description discloses idempotency ('Safe to repeat'), auth requirements (API key, deal ownership), value currency interpretation with a concrete example, and notes-replace-not-append semantics. This adds substantial behavioral context beyond boolean hints, with no contradiction.

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 compact yet information-dense: first sentence states the core function, second covers usage guidance, third explains idempotency and auth, fourth clarifies unit and string semantics. No filler or repetition—every sentence 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 mutation tool with no output schema, the description covers all essential aspects: purpose, alternative usage, partial updates, idempotency, auth/ownership, currency units, replacement behavior, and status effects. It is fully sufficient for an agent to select and invoke the tool correctly.

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 covers all parameters with descriptions (100% coverage), giving a baseline of 3. The description enriches this with partial-update behavior ('Only the fields you pass are altered'), an explicit currency example, and the replace/append distinction for notes, which are not evident from the schema alone.

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 precise verb+object+fields: 'Change a deal's status, value, or notes.' It explicitly differentiates from the sibling move_deal_stage, clarifying that this tool is for value/notes while stage moves belong to the sibling. This is a model of purpose clarity.

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?

Provides explicit guidance: 'For moving a deal along the pipeline board prefer move_deal_stage, which is the same operation expressed in stage terms; use this one for value and notes.' Also explains the consequence of setting status to closed/lost, offering clear when-to-use and exclusion information.

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