Create or update model

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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds the *reason* ('each call without model_id creates another model') and the underlying mechanism (PATCH on update). That is useful context beyond the annotations, though it says nothing about permissions or the effect of an update on unmentioned fields.

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?

Front-loaded with the key distinction (create-or-update, not idempotent) followed by two tight bullets. Every sentence carries actionable information with no filler.

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?

An output schema exists, so return-value detail is not required, and the description fully covers the create/update dichotomy, the non-idempotency trap, and which fields matter. An agent has everything needed to invoke it 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 description coverage is 0%, so the description must compensate, and it largely does: it explains that project_id+name drive creation, that model_id switches the call to update mode, and that description is optional. It does not clarify what happens to unspecified fields on PATCH, leaving a small gap.

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?

States a specific verb+resource ('Create or update a model') and explicitly delineates two operating modes (create vs update/rename). This distinguishes it from siblings like create_model_version and get_model without opening their schemas.

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?

Gives explicit conditions: call with project_id and name to create, add model_id to update/rename. It even warns that repeated calls without model_id create duplicates. It does not name an alternative sibling (e.g., get_model to inspect first), so it falls just short of a full when/when-not treatment.

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