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

Annotations already declare readOnlyHint=true, so the description needn't explain safety. It adds valuable context beyond annotations: the tool is scoped to the active Space, and space_id overrides that binding for this one call without changing the session. No contradictions.

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 sentences with zero waste. The first front-loads exactly what is returned, and the second immediately covers the Space scoping and alternative.

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 read-only tool with no output schema, the description adequately conveys the return values and the Space-scoping behavior. It leaves a minor gap: with zero required parameters, it does not clarify how optional business_id behaves (e.g., omitted means all businesses or a default).

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 coverage is 100%, so both parameters are fully documented. The description reinforces the space_id override semantics (matching the schema) but adds no new meaning for business_id, so baseline 3 applies when the schema does the heavy lifting.

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 states exactly what the tool reports: per-business competitor tracking limits, current tracked count, and the monthly ad library lookup allowance. It distinguishes itself from siblings like get_competitor and list_competitors by focusing on plan quotas/allowances rather than entity data, though it doesn't use an explicit verb.

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 clearly explains Space scoping and explicitly names set_active_space as the alternative for switching, plus the space_id override for a single call. It does not say when to prefer this over adjacent read tools such as get_competitor_coverage or account_summary, but provides clear context for the Space dimension.

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