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

Goes well beyond the annotations: it discloses that changing purchase_date, warranty_months or reminder_offsets recomputes warranty_until and CANCELS the old pending reminders before rescheduling — a real destructive side effect that destructiveHint=true only hints at. It also exposes the two-phase confirmation handshake and the exact response fields the agent must act on.

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?

Front-loads the verb and target, then the editable set, then consequences, then the confirmation protocol. The field list is long but earns its place since the schema has no descriptions, and the side-effect and confirmation sentences are the highest-value content.

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?

With no output schema, the description carries return-flow disclosure and does it well for the confirmation path. The main remaining gap is PATCH semantics: it never says whether omitted fields are left unchanged or whether fields not listed are rejected (additionalProperties=false makes this material), and it doesn't cover failure or permission behavior.

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 0% across 12 parameters, so the description does real work by naming every editable field and flagging which three trigger recomputation and reminder cancellation. However, it mostly restates schema property names without adding meaning for ambiguous ones — currency format, the distinction between receipt_id and document_id, the units assumed for reminder_offsets, or the null-vs-omit semantics for price/receipt_id/document_id.

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 with scope ('Update one of the caller's warranties by id') and enumerates the editable fields, which cleanly separates it from add_warranty_item and delete_warranty_item in the sibling list.

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 states the ownership constraint ('Only the caller's own warranty is reachable') and, more importantly, documents that this tool never writes directly — it returns status='confirmation_required' with an action_id and plan_token, and the write occurs only via confirm_action. That names the alternative tool and the condition that selects it.

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