Spawn a persistent presence

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

With no annotations, the description carries the behavioral burden. It does disclose that the presence is persistent, that generative work happens 'inside this contract,' and that 'the contract itself never changes,' plus the return of a presenceId. However, it omits side-effect details such as whether an artifact is consumed, whether spawning twice overwrites, or permission requirements, and the final sentence is somewhat cryptic.

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 compact and front-loaded with lifecycle context before diving into parameters and return values. The final sentence about 'generative work' is somewhat vague and may not earn its place as clearly as the rest, but overall the structure is efficient.

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 tool with 3 parameters, no annotations, and no output schema, the description covers the essential context: what it creates, how it relates to addArtifact, what it returns, and what to do with that return value. It is reasonably complete, though a note about error conditions or idempotency would make it fully self-sufficient.

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?

The schema already covers 100% of parameters, and the description adds meaning beyond it: it gives a concrete example for sourceContext, explains that artifactId is an alternative to fresh derivation, and clarifies that styleHint is optional. This enriches the bare schema descriptions without redundancy.

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: 'Creates a persistent presence derived from the given context.' It also positions the tool as 'step 1 of 3 (spawn / animate / retire)' and references animatePresence and retirePresence by name, making it easy to distinguish from the siblings and from addArtifact.

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 lifecycle is explicit: this is step 1, the returned presenceId feeds animatePresence and retirePresence, and the tool can be used either from fresh context or from a held artifact via addArtifact. It does not explicitly state when not to use it (e.g., versus manifestHighlight), so the guidance is clear but not exhaustive.

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