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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description still adds real behavior: page-bounding, the limit default shifting to 5 under detail=full, cursor stability requirements, and conditional inclusion of product_link. It stops short of auth/rate-limit or error behavior, 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?

Front-loaded purpose followed by clear REQUIRED/Optional/EXAMPLE sections, so it scans well. It is dense and the 'Mirrors the Meta sister product's templates_list' sentence adds little for tool selection, keeping it out of 5 territory.

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?

With no output schema, the description enumerates the returned fields, documents every user-facing parameter, and covers pagination, so an agent has everything needed to call it correctly. The one undocumented field, connection_context, is an injected context token rather than a caller decision.

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 carries the full burden and does so thoroughly: limit range and dual default, cursor semantics, detail enum with the effect on row completeness, and product_ref's conditional applicability. This is strong compensation for an undocumented schema.

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 names a specific verb and resource ('List saved ad templates for the authenticated user') and immediately scopes it ('bounded summary page') with the exact fields returned. It explicitly distinguishes itself from the sibling templates_get, so an agent can route between the two without opening either schema.

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?

It gives explicit routing ('Use templates_get for one template's params, naming and defaults') and states conditions for the tricky parameters (product_ref ignored unless product cards are enabled; cursor requires keeping detail/limit identical). It also disambiguates the resource ('A template is an ad-creation template, not an insights breakdown').

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