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

Goes well beyond the annotations, which only declare readOnly/destructive/idempotent/openWorld flags. The description discloses the re-basing side effect (NBV and remaining life re-base from occurred_on), the invariant that purchase_date is NEVER changed, the validation rule that work adding neither amount nor life is rejected, and the required auth scope.

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?

Five dense sentences, each earning its place: purpose with examples, required-field validation, side effects, the date-semantics caution, and alternatives/prerequisite/scope. Front-loaded with the core purpose and no boilerplate.

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 9-parameter mutation with no output schema and thin annotations, the description covers everything an agent needs: required inputs, side effects, invariants to protect, alternatives, prerequisite lookup, and auth requirements.

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 description coverage is 100%, so the baseline is 3. The description adds value beyond it by synthesizing the cross-parameter constraint ('at least one of capitalized_amount or added_life_years') into an explicit rejection rule and by pointing to list_assets for resolving asset_id, which the schema does not express.

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 and resource ('Record capital work that ALREADY extended a facility asset's life') and grounds it with concrete examples (elevator modernization, boiler retube). This clearly distinguishes it from siblings like create_asset_lifecycle_event and create_asset_condition_assessment without opening their schemas.

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?

Explicitly routes the agent: use asset_lifecycle_events for future work, a condition assessment for observations, and record this instead when a user asks to change an in-service date. It also names a prerequisite ('Call list_assets first to resolve asset_id') and states the required scope.

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