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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral detail beyond that: it enumerates the status values, explains the `outcome` pickup semantics, and defines the `answered_at` non-null condition. Auth and rate-limit behavior remain undisclosed, so not 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?

Four sentences, front-loaded with the core purpose, then progressively detailing return contents. Every sentence carries information, though the enumeration of status/outcome values is dense. 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?

With no output schema, the description appropriately carries the return-value burden and does so thoroughly (per-turn rows, status, duration, outcome, answered_at). For a read-only two-parameter getter this is nearly complete; only cross-tool routing guidance is absent.

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 both parameters are already fully documented in the schema (including where call_id comes from). The description only restates 'by call_id' and says nothing about in_workspace, adding no meaning beyond the schema. Baseline 3 applies.

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 ('Get the structured transcript and final state of a voice call') plus the access key ('by call_id'). This is clearly distinguishable from the list-oriented siblings calls_list_history and calls_list_active, which the agent can infer without opening a 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?

Usage is implied rather than stated: the note that it 'Returns active turns if the call is still in progress' tells the agent it can be used on live calls, but there is no explicit when-to-use guidance and no routing to alternatives (e.g. when to prefer calls_list_history). Adequate but with a clear gap.

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