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

Annotations indicate a mutating, non-idempotent, open-world operation, and the description adds valuable behavioral notes: traits are never inferred (explicitly stated) and each reference fills a durable slot. This goes beyond what annotations convey, though it does not mention side effects like overwriting or return values.

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?

Two concise sentences, front-loaded with the core purpose and followed by a key behavioral constraint. Every word adds value; no filler or 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?

The tool has a nested reference structure and an output that is not documented (no output schema). While the schema covers the input details, the description omits any mention of return values or error behavior, which could leave an agent uncertain about the result. However, given the complexity and the richness of the schema, the description is largely adequate.

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 80% and already describes most parameters, including the 'Never inferred' note on traits. The description adds a little context (durable slots) but largely relies on the schema. Since coverage is high, the baseline 3 is appropriate.

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 creates a reusable avatar from an ordered set of references (generated views, workspace files, or URLs). It distinguishes itself from related siblings like save_generated_avatar or upload_avatar_from_chat_file by emphasizing the multi-source reference input.

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 the tool is used when you have multiple reference sources to combine into one avatar, but it does not explicitly name alternatives or conditions for when not to use it. It gives some context but lacks explicit routing guidance compared to siblings like save_generated_avatar.

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