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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Update' which implies mutation, but it does not disclose whether the update is partial or full replacement, whether merge_keys controls merging behavior, what happens to unspecified fields, or any side effects. This is a significant gap for a mutation tool.

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 a single short sentence, which is concise, but it is under-specified. It front-loads the verb and resource but omits essential context about the update semantics. It earns a 3 because it is not verbose, but it sacrifices necessary information for brevity.

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 tool has 6 parameters, no output schema, and no annotations, the description is incomplete. An agent cannot determine how to correctly invoke the update, what the merge_keys parameter does, or what the expected result is. The sibling tools suggest a prepare/confirm pattern, but this tool does not follow that pattern, and the description does not clarify its place in the workflow.

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, but it only mentions 'metadata' generically. It does not explain the meaning of merge_keys, funnel_events, decision_rules, or how they relate to the update. The parameter names are somewhat self-explanatory, but the critical merge_keys behavior is left entirely to inference.

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 ('Update') and resource ('AdsAgent-owned product-card metadata'), which clearly identifies the tool's function. It distinguishes from siblings like google_ads_product_card_delete and google_ads_product_card_save by focusing on updating metadata, though it doesn't explicitly contrast with them.

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?

No guidance is provided on when to use this tool versus alternatives like google_ads_product_card_save or google_ads_entity_update_confirm. The description implies usage for updating product-card metadata but does not state prerequisites, exclusions, or conditions that would help an agent choose it over similar tools.

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