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

Annotations already declare this is a write operation (readOnlyHint=false) and not destructive. The description adds valuable context: the backend automatically analyzes the image if no description is supplied, and the tool returns a location_id for later use. This goes beyond the annotations by disclosing the auto-analysis behavior and the reusable nature of the created reference.

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 with no filler. It front-loads the core action, then adds the conditional behavior, then a usage hint. Every sentence earns its place, and the structure is clean and scannable.

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?

Given the 6 parameters, 2 required, and nested objects, the description covers the key behavioral aspects: what it creates, the auto-analysis fallback, and the returned ID. It does not explain error handling or permissions, but the schema and annotations already cover the parameter details and safety profile. For a create tool, this is reasonably complete for an agent to invoke correctly.

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 each parameter is documented in the schema. The description adds minimal extra parameter-specific meaning: it clarifies the behavior of the 'description' parameter (if omitted, backend analyzes the image). This is a useful nuance but does not substantially compensate for the schema already covering all parameters. 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 states a specific verb ('Create'), a clear resource ('reusable location/scene reference'), and the source ('from an image URL'). It clearly distinguishes from sibling tools like create_tag or create_art_direction by focusing on location references. The downstream usage hint ('Use the returned location_id in propose_brief/update_brief') further clarifies its purpose.

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 the tool (to create a location reference for briefs) and gives a downstream usage hint. However, it does not explicitly state when not to use it or name alternatives like update_brief or get_location. Still, the purpose is clear enough that an agent can infer appropriate usage without explicit exclusions.

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