retell_update_call

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

With no annotations provided, the description must disclose behavioral traits, but it only says 'Update metadata or data storage settings.' It does not clarify whether metadata is merged or replaced, whether the data_storage_setting override is permanent, or any side effects or permission requirements. This leaves significant ambiguity for a mutation tool.

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?

The description is a single, concise sentence that front-loads the action and scope. Every word earns its place, with no fluff or repetition.

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?

Despite the schema covering parameter descriptions, the overall description is insufficient for a tool with no annotations and no output schema. It does not explain update semantics (merge vs replace), behavior when only some fields are provided, or any response expectations. An agent would need more context to invoke this correctly beyond just reading the schema.

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%, with each parameter (call_id, metadata, data_storage_setting) having a clear description. The tool description adds nothing beyond the schema, so the baseline score of 3 is appropriate.

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 description clearly states the action ('Update') and the resource ('existing call'), along with the specific scope ('metadata or data storage settings'). This distinguishes it from sibling tools like retell_get_call or retell_delete_call, which have different verbs and purposes.

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 gives no explicit guidance on when to use this tool versus alternatives. While 'existing call' implies it is for post-creation updates, there is no mention of scenarios, exclusions, or relationships to related tools like retell_create_phone_call or retell_update_agent. The usage context is only implicit.

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