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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds meaningful behavior beyond that: the result is AI-generated, includes next steps, and may be unavailable depending on plan or whether summarization occurred. It stops short of describing the response shape or what a not-summarized call returns.

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?

Two tight sentences that front-load the purpose and then the availability caveat; the REST endpoint reference is compact and useful. Slightly dense with three separate pieces of information but no filler.

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 one-parameter read with no output schema, the description covers purpose, the content of the result (summary + next steps), and the main failure condition. Only the exact return structure is unstated, which is minor given the tool's simplicity.

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 coverage is 100% and the single callId is fully documented in the schema (including the 'AC' prefix). The description adds nothing beyond 'by its id', so the baseline 3 for schema-covered parameters 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?

States a precise verb and resource ('Get the AI-generated summary and next steps for a call by its id'), which cleanly separates it from siblings like openphone_get_call_transcript or openphone_get_call_recordings. An agent can identify the tool's output without opening the schema.

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?

It gives a real precondition ('Availability depends on your plan and whether the call was summarized'), which implies when the call may fail. However, it never routes the agent between this tool and the closely related openphone_get_call / get_call_transcript siblings, so the 'use this instead of that' guidance is left to inference.

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