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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds substantive behavior beyond that: snapshot-bound pagination, the 'unknown, not empty' semantic for unsynced data, and the no-live-pull guarantee. It omits freshness/rate-limit or auth details, so not a 5.

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?

Three tight sentences with the core purpose front-loaded and no filler. Each sentence adds a distinct, load-bearing constraint (snapshot source, unknown-vs-empty semantics, pagination rule).

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 a 7-parameter read tool with no output schema and low schema coverage, the description supplies the key behavioral caveats but leaves most parameters unexplained. It is adequate for the tool's core semantics but incomplete for correct invocation of its filters.

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 only 14% (just customer_id documented), so the description must carry parameter meaning. It only partially does: it explains continuation must be paired with the same customer and filters, but sort, search, page_size, asset_type and connection_context remain undocumented in both schema and description.

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 and resource: reading the last complete stored creative inventory, and clarifies it is a stored snapshot rather than a live Google pull. It does not name the closest sibling (google_ads_assets_list) to disambiguate, so an agent must infer which inventory source it wants.

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?

Provides an explicit rule for continuation reuse ('same customer and filters') and warns that missing sync means unknown, not empty, and that it never pulls live data. However, it never states when to prefer this tool over siblings like google_ads_assets_list or creatives_list_cloud, leaving the selection decision implicit.

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