Call and play audio

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

Annotations already declare openWorldHint and destructiveHint; the description adds value with 'real phone call' (an externally visible, non-retryable side effect) and 'Returns a request ID', so the agent knows the call is asynchronous and must be polled. It omits cost/irreversibility framing, but the keep_record parameter description covers record retention, so remaining gaps are minor.

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 sentences, zero filler, with the action and format constraints front-loaded and the return value stated last. Nothing is repeated from the title alone.

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 5-parameter outbound-call tool with no output schema and full schema coverage, this is nearly complete: it covers the action, the media format, the file-location constraint, and the return value. It could still mention cost or that a live agent/answering machine affects outcome, but nothing needed to invoke it correctly is missing.

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%, so baseline is 3; the description earns more by constraining audio_file to PCM 16-bit, 8 kHz mono and to a location 'inside the configured file folder', which the schema's bare 'Full path to the WAV file' does not convey. It adds nothing about caller_id, keep_record, or schedule_minutes, but the schema already documents those fully.

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 gives a specific verb and resource ('Place a real phone call') plus the exact payload ('plays a WAV file'), which distinguishes it implicitly from call_text and call_ivr. It stops short of naming a sibling or stating the contrast explicitly, so it is clear but not fully differentiated.

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 only implied: an agent can infer this is the audio-playback call path versus texting or IVR, but there is no explicit 'use this when' statement, no exclusion of alternatives, and no prerequisites (e.g., that caller_id must be pre-provisioned in Voicent, which only appears in the schema).

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