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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true), the description discloses three behaviors an agent could not infer: the action consumes credits, it is rate-limited to once per week per company, and it only works during business hours. It does not say whether a human actually answers or a voicemail is left, nor what a failed attempt looks like, which are the remaining meaningful gaps.

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 short sentences with no waste: the action first, then the operating constraints, then the cost. Each sentence carries distinct information the agent needs, and the front-loaded verb makes the tool's identity immediate.

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 four-parameter, non-destructive but credit-consuming outbound action with no output schema, the description covers cost, timing, and rate limits – the facts most likely to cause a mis-invocation. It stops short of describing outcomes (connection vs voicemail, error conditions) or what 'principal' refers to, leaving a small but real gap.

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 all four parameters are already documented in the schema; the baseline is 3. The description adds modest meaning – "short hello" constrains the note content and "pointing to your principal" hints at what target is for – but it introduces no format or syntax detail beyond what the schema provides.

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?

"Reach a human at a company's main line and leave a short hello pointing to your principal" states a concrete verb (call/reach) and resource (company main line) and implies a voice channel, which distinguishes it from siblings like send_email and send_text without naming them. It is not tautological, but it never explicitly contrasts itself with ask_herman or get_a_human.

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 description supplies operating constraints – business hours only, once per week per company – which implicitly tell the agent when this is permissible. It does not say when to prefer this over the email/text siblings or what prerequisites (campaign, credits available) must hold, so the when-to-use guidance remains implied rather than stated.

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