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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds the account-level aggregate scope and the metrics returned, but does not describe output structure, pagination, or other runtime behavior beyond that. This is a reasonable value-add, not a rich disclosure.

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 no filler. The action and metric list are front-loaded, and the purpose clause earns its place by explaining why this tool exists relative to organic profile performance.

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 five-parameter read-only tool with no output schema, the description lists the expected returned metrics and names the relevant sibling alternative. It does not mention date-range defaults or campaign scoping, but those are fully covered in the schema, so nothing critical is missing.

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 the schema fully documents all five parameters, including defaults and the optional ad_account_id behavior. The description does not add parameter-specific meaning beyond the schema, which matches the baseline for high coverage.

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 a specific action, resource, and scope: "Fetch account-level LinkedIn Ads performance" and lists concrete metrics. It also distinguishes itself from the sibling get_ad_performance_breakdown by explicitly contrasting account-level vs per-ad detail.

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?

The description provides clear when-to-use context by framing the tool as the account-level paid-performance comparison and explicitly points to the correct alternative: "For per-ad detail use get_ad_performance_breakdown." This lets an agent route correctly without opening the sibling schema.

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