emu_append_call_session_event

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

No annotations are provided, so the description carries the full burden of disclosure. It reveals this is an append operation (suggesting immutability of prior events and session growth), but it doesn't state whether events are validated against a schema, whether timestamps must be monotonic, whether duplicate events are rejected, whether the event list is persisted, or what happens if the session doesn't exist or is already terminated. For a mutation tool, this is minimal disclosure.

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 sentence that efficiently conveys the core action. It's concise without being wasteful. However, it's slightly under-specified rather than optimally sized — an extra sentence explaining event type options or prerequisites would not have been padding.

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 write operation with no annotations, no output schema, nested object parameters, and 18 sibling tools, this description is incomplete. An agent cannot reliably know whether to call this versus emu_call_action, how to construct the payload, what timestamp format to provide, or what the response will be. It needs more context about the call session lifecycle and event type semantics.

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 0%, and the description names none of the four parameters. The agent must infer that 'id' refers to the call session id and 'type' refers to an event type enum, but nothing in the description confirms this mapping. The 'payload' object and 'timestamp' parameter get no explanation at all, and the timestamp format (epoch vs ISO vs ms) is undocumented. With 0% coverage, the description needed to compensate and did not.

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 'Append an event to a canonical v2 call session' has a specific verb (append), a resource (event), and a target (canonical v2 call session). It distinguishes itself from siblings like emu_create_call_session and emu_terminate_call_session by describing a mutation on an existing session rather than creation or termination. However, it doesn't explain what a 'canonical v2 call session' is or how it differs from a regular call session, leaving some ambiguity. It also doesn't clarify whether 'event' here refers to a call event (like originating or connected) or something else.

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 guidance about when to use this tool versus alternatives such as emu_create_call_session, emu_call_action, or emu_simulate_call. With 70+ sibling tools, an agent has no way to know whether appending a session event is the right action for a given scenario. The phrase 'canonical v2' hints at a newer format, but there's no explicit when/when-not guidance or mention of prerequisites (e.g., the call session must already exist).

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