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

Beyond the readOnly/idempotent annotations, it discloses that access tokens are never returned, that paused and error pixels still appear with their status, and that their events are skipped until resumed or fixed. That is exactly the kind of side-effect and filtering context annotations cannot convey.

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?

Purpose and the critical id-vs-pixelId rule come first, followed by field list, safety note, and doc link. The field enumeration is dense but earns its place because no output schema exists; only mildly list-heavy.

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 supplies the return shape, the status semantics, the token-safety guarantee, and a pointer to the authoring guide. An agent has everything needed to call it and to use the result correctly.

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?

The tool takes no parameters, so there is nothing to disambiguate and the baseline is 4. The description compensates by enumerating the returned fields and clarifying which identifier field feeds into downstream configuration.

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 ('List this account's connected Meta pixels') and scopes it to a concrete use case ('for Meta Pixel event (meta_capi) automations'). No sibling tool covers this resource, so the resource name alone distinguishes it.

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?

Gives a clear when-to-use context (populating Meta Pixel automations) and an explicit operational rule: use a row's id, not pixelId, as actionConfig.metaPixelId. It does not name a substitute tool or state when not to call it, but none of the listed siblings are plausible alternatives.

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