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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds meaningful behavior beyond that: the email is masked (a privacy guarantee an agent should not assume it can read raw), scopes are surfaced so permission checks are possible before acting, and brand names are capped at ten, warning that the list may be truncated.

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?

Two dense sentences with zero filler: the return payload is front-loaded, then the usage cue and sibling disambiguation. Every clause carries information an agent would otherwise have to guess.

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 an output schema present and annotations covering the safety profile, the remaining burden is small, and the description still contributes the masking and truncation caveats. Only the lack of any note on auth or failure behavior keeps it from being fully complete.

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 100% and the single response_format parameter, including its enum and the note that table is unavailable, is fully documented in the schema. The description adds nothing about formatting, which is acceptable given the schema already carries that meaning.

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+resource ("Returns the account behind this connection") and enumerates exactly what comes back: display name, masked email, granted scopes, brand count, up to ten brand names. It also explicitly separates itself from list_brands, which returns brand ids, so an agent can tell the two apart 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?

"A first call for confirming which StealAds account and permissions are in use" gives a clear situational trigger, and the list_brands pointer supplies the alternative for the brand-id use case. It stops short of explicit exclusions or ordering guidance for the rest of the catalog, but the intended context is unambiguous.

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