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

Goes well beyond annotations (readOnlyHint=false, openWorldHint=true) by disclosing that it returns a call link which must be handed to the user, and that a recap becomes available afterwards via check_pally with turn_id. Doesn't cover cost, permissions, or failure modes, keeping it short of a 5.

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-loaded with the action and trigger, then return value, then follow-up. The sentence about the call view ('or in the call view when the app shows one') is slightly redundant padding but everything else earns its place.

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 params and no output schema, the description covers initiation, the returned artifact, how the user completes the interaction, and the post-call recap path — enough for an agent to call it and handle the result correctly.

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?

Zero parameters, so baseline is 4; the description usefully documents the output value (call link) and the turn_id that must be passed to check_pally, which the absent output schema would otherwise leave unexplained.

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 ('Start a live voice call between the user and Pally') and the trigger conditions distinguish it from message_pally and check_pally immediately.

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 says when to use it (user wants to talk live/by voice or asks to call Pally) and names the alternative path ('to have Pally ring the user's phone instead, ask Pally through message_pally'), plus the follow-up tool check_pally for the recap.

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