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

Annotations declare destructiveHint=true, and the description usefully adds that provenance/source_* fields are immutable after save and must be refreshed via reverse_engineer, plus the music_info validation behavior. These add real context beyond the annotations, though it doesn't cover auth requirements or error behavior.

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 core action, then structured REQUIRED/OPTIONAL/EXAMPLE sections. The music_info sentence is dense but earns its place; minor verbosity in the Meta mirroring reference.

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 an 11-parameter mutation tool with 0% schema coverage and no output schema, the description covers the most surprising fields (aliases, immutability, music_info) but leaves several parameters (campaign_params, naming fields, connection_context) and the response behavior unexplained.

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 compensates by explaining the adset_params/adgroup_params alias relationship, the immutability of source_* fields, and the music_info={music_id:...} setting on ad_params. It omits details on naming fields and connection_context, which the schema doesn't describe either.

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 (Update) and resource (existing saved template), scoped to the authenticated user's templates, and names the Meta endpoint it mirrors. Clearly distinguishable from templates_create, templates_delete, and templates_get.

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?

Explains the patch semantics (only passed fields updated) and names an alternative workflow for provenance fields (re-run templates_reverse_engineer). However, it doesn't explicitly say when to use this vs templates_create or when not to use it.

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