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

Annotations already declare readOnly=false, openWorld=true, idempotent=true and destructive=false, and the description reinforces those with real context: it mutates the account, consumes a tracking slot, and is idempotent even at the limit. It adds the most valuable trait annotations cannot express — that there is no MCP removal tool and brands must be removed on the website — plus background ingestion behavior, which is exactly the kind of side-effect disclosure that matters.

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 with the action, then layered with prerequisites, side effects, return fields, and the removal caveat — nearly every clause carries non-duplicated information. It reads slightly as a compressed fact list rather than flowing prose, but there is no filler to cut.

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 two-parameter mutation with no output schema, the description covers everything an agent needs: prerequisites, slot consumption, idempotency, async ingestion lag, the returned fields (tracked_count, tracked_limit, remaining_slots, ingestion_state), and the missing removal path. Nothing material is left to inference.

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%, so both parameters are already documented (page_id as Meta page ID string, brand_name as display name not a URL). The description only restates the requirement ("Requires a Meta page_id and brand_name") without adding format, constraint, or validation detail beyond the schema, so the baseline 3 applies.

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?

Uses a specific verb+resource ("Add a known advertiser to your tracked brands") and immediately scopes it against the read path ("before reading its ads"). The closing line explicitly separates it from search_advertisers/find_similar_advertisers ("Does not search Meta or resolve advertiser names or URLs"), so the agent can pick the right sibling without opening schemas.

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 triggering condition (call this before reading an advertiser's ads) and clear exclusions (not for searching Meta or resolving names/URLs). It doesn't name the specific alternative tool to use in those excluded cases, which is the only thing separating it from a 5.

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