Set the token image of an actor

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

The description adds useful behavioral context beyond annotations, such as how the ring behaves when enabled and how ringColor defaults to disposition-based coloring. However, despite destructiveHint=true, it does not explain the overwriting or potentially destructive consequences of changing the prototype token image.

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 three sentences with no filler, front-loading the main purpose and then adding only relevant optional behaviors. Each clause adds actionable information without repetition of schema details.

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 7-parameter mutation tool with no output schema, the description covers the target resource, identifier resolution, optional fields, and ring semantics. It is slightly incomplete regarding what happens on failure or whether existing placed tokens are affected, but these are minor gaps given the schema covers every parameter.

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 the baseline is 3. The description adds genuine value by explaining behavior not fully explicit in the schema, such as ring color defaulting by disposition, ringScale being usually unnecessary, and the actor being found by id or exact name.

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 states a specific action on a specific resource: 'Set an actor's prototype token image' and lists the optional modifications. The word 'prototype' and 'actor' clearly distinguish this from sibling token tools like update-token, which operate on placed scene tokens.

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 implies when to use it: when an actor's prototype token image needs to be set, optionally with portrait, token name, or ring changes. It does not explicitly contrast with alternatives such as update-token or manage-actors, nor does it state when not to use this tool.

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