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

Annotations already declare readOnly, idempotent, non-destructive and non-open-world, so the safety profile is covered. The description adds genuine behavioral detail beyond that: it defines what each count means and discloses the dedup rule for sites_promoting_any ('counts each site once however many competitors it promotes'), which an agent could not infer from the schema.

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?

Content is densely packed into one sentence followed by a short clarifying clause about the dedup semantics. No filler, and the most important framing (what the counts represent) is front-loaded.

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 carries the burden of explaining return fields and does so for four of them. The only gap is that it never says the result is scoped to a project/app_id or how the list is ordered, but for a simple read-only list this is close to 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 app_id parameter is fully documented there, including the 'omit to use most recently added project' default. The description adds nothing about parameters, 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?

The description names the resource (competitors) and precisely what it returns — roster counts, mentions, distinct promoting sites, and multi-brand creators — so an agent knows the payload without opening a schema. It does not, however, explicitly name the verb or distinguish itself from nearby siblings like get_competitor_suggestions or get_partners, so it stops short of a 5.

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?

There is no statement of when to call this versus alternatives (e.g. get_competitor_suggestions for pending suggestions, add_competitor for mutation). Usage is only implied by the noun 'Your competitors'. No prerequisites or exclusions are given.

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