Update a YouTube ad

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

With no annotations provided, the description carries the full transparency burden. It discloses the important side effect of emailing followers when status is set to 1, the membership prerequisite, and the error for free accounts. It could be more detailed about return values or other edge cases, but the key behavioral impacts are covered.

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 concise and well-structured, with the core behavior stated first and important caveats following. Every sentence adds value, and there is no redundant or filler content.

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 moderate complexity and absence of an output schema, the description is sufficiently complete. It covers the operational context, ownership requirement, partial-update semantics, the email side effect, and membership prerequisite. No critical missing information prevents correct invocation.

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 the baseline is 3. The description adds meaningful context beyond the schema: youtube_ad_id must belong to the user, status 1 emails followers, and youtube_link is re-derived into a video ID. This extra detail helps the agent understand implications that raw schema constraints do not convey.

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 partially updates an existing YouTube ad owned by the user, with only supplied fields changing. It uses a specific verb ('updates'), identifies the resource ('YouTube ad'), and distinguishes it from creation by emphasizing 'existing' and 'partial update'.

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 provides clear usage guidance: it updates existing ads, only supplied fields change, and it warns that setting status to 1 emails followers once ever. It also notes the paid membership requirement and that free accounts receive an error. It does not explicitly name alternative tools like create_youtube_ad, but the 'existing' and 'partial update' language makes the intent clear.

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