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

Adds real behavior beyond annotations: a 5-attempts-per-code limit and the fact that retries without an idempotencyKey execute the operation again, which is consistent with idempotentHint=false. However, destructiveHint=true is never explained — an agent cannot tell whether confirming consumes the number, mutates its state irreversibly, or what the 5th failed attempt triggers. With annotations already covering the safety profile, this leaves the most consequential trait undisclosed.

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?

Three tight sentences with no filler; the lockout and idempotency rules are packed into short clauses. The opening 'Step 8: Place a test call' is the weakest part — it spends the front-loaded position on sequencing and a phrase that suggests a different sibling tool.

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 4-parameter mutation with no output schema, the description covers the input source, the failed-attempt budget, and retry semantics, which is most of what an agent needs. Missing is any statement of what success yields (number confirmed/attached to the business) and what a rejected code or exhausted attempts returns.

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 50% (businessId and idempotencyKey are documented; code and number are only pattern-constrained). The description adds genuine meaning for `code` by explaining it is the value read by the verification call, but the idempotencyKey retry note largely repeats the schema's own wording, and `number` gets no elaboration beyond its E.164 pattern. Roughly baseline for this coverage level.

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: confirm a number using the 6-digit code that its verification call read aloud. The phrase 'its verification call' implicitly links it to ringkit_verify_destination, but the pairing is not stated outright, so the sibling distinction is inferred rather than declared. The leading 'Step 8: Place a test call' framing is slightly at odds with a confirmation action and brushes against the separate ringkit_test_call 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 clear situational context: use it once the verification call has been answered and the recipient has the code, with the caveat that only the answering party possesses it. It also gives retry guidance (reuse idempotencyKey) and a lockout rule (5 attempts per code). It stops short of naming ringkit_verify_destination as the prerequisite step or saying what to do after the attempt budget is exhausted.

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