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

Annotations already declare non-read-only, non-idempotent, closed-world, and the description adds genuinely non-derivable behavior: language fields are rejected with a 400 naming the field when the engine has has_language_axis false, and locale overrides stay draft until an explicit publish step. It does not state what the response contains (e.g., the new agent's id) or whether creation is atomic across the nested objects.

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?

Three sentences, front-loaded with the purpose, and no filler. However, terms like 'first-class', 'shared stack', and 'explicit voice-stack publish command' are used without definition and add density without clarity.

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 17-parameter creation tool with nested objects and no output schema, the description is thin: it never says what is returned, what defaults apply, or how the many optional fields interact. It covers the highest-risk validation rule well, which keeps it at minimum-viable rather than inadequate.

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 only 18% across 17 parameters, so the description must compensate and largely does not: model, voice, transcriber, webhook_url, begin_message, first_message, system_prompt, audio_stream_url and the required project_id/name are never explained. It does add real cross-parameter semantics for languages and language_profiles via the engine capability gate and the draft/publish lifecycle, but that covers a small fraction of the surface.

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 names a specific verb and resource (create a Skysay agent) and enumerates the three mutually exclusive modes, so the agent knows exactly what the call produces. It does not distinguish itself from siblings that also create agents (connect_external_agent, duplicate_agent) or from update_agent.

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 through the mode enumeration and the note that hosted mode is the one that accepts stacks and languages, but there is no explicit statement of when to choose this tool over connect_external_agent or duplicate_agent. The mention that locale overrides need a later publish command is a useful sequencing hint but is phrased as a fact rather than guidance.

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