build_character_effect

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states 'Read-only' and that it returns '{ command }', which are critical behavioral traits. It also adds the event command IDs (212/213) and character targeting context, but does not detail error behavior or side effects of the generated command when inserted.

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 two sentences long, front-loaded with the core purpose, and every phrase adds value. It efficiently packs the command types, insertion context, characterId mapping, and read-only behavior without redundancy.

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?

The tool has 5 parameters and no output schema, but the description provides the essential context: it returns a command object for insertion, identifies the exact event commands, and explains characterId values. It does not detail the internal structure of the returned command, but for a builder that partners with insert_event_commands, this is 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?

Schema description coverage is 100%, so baseline is 3. The description mentions characterId semantics and the id's dual role, but these are already fully described in the schema. It adds no significant parameter-level meaning beyond what the structured schema already provides.

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 clearly states the tool builds a Show Animation (212) or Show Balloon Icon (213) event command for insertion via insert_event_commands, specifying the exact verbs and resources. It distinguishes itself from sibling builders by naming the specific event command types and their target character scope.

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 explicitly mentions the intended use case ('for insertion via insert_event_commands') and clarifies the characterId semantics (player, this event, or event id). It implies the tool is for building these two specific command types among many sibling builders, though it does not name alternatives or exclusions.

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