draft_call

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

With no annotations, the description carries the full behavioral burden and does well: it discloses the return payload (call id, normalised number, opening line, briefing), the critical consequence that omitting voicemail makes the agent hang up, and the progress-event toggle. It omits auth requirements, idempotency, and whether the draft expires or must be confirmed.

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?

Purpose is front-loaded, then behavior and field semantics follow in a logical order without padding. It is dense but every sentence conveys operational information rather than restating the name.

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?

An output schema exists, so the return-value detail is a bonus rather than a necessity. For a 10-parameter mutation-ish tool with zero annotation and zero schema-description coverage, however, half the parameters (principal, facts, region, language, must_not) are left unaddressed.

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 10 parameters, so the description must compensate, and it only explains voicemail, topic, and progress in depth. Facts, principal, region, language, and must_not receive no semantic guidance, though 'to' and 'goal' are inferable from the purpose statement.

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 opening verb+resource+scope, 'Prepare a call without dialling', is precise and immediately signals this is a pre-dial stage. It implicitly separates the tool from confirm_call's dial action, but no sibling is named explicitly, so the differentiation is inferred rather than stated.

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?

The 'without dialling' framing implies this is the step before confirm_call, and the voicemail warning implies when the field is needed. However, the description never names an alternative or states an explicit when/when-not condition, leaving the workflow position to inference.

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