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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds genuinely new context: nothing changes state, reads are free, and only execute bills the tool. It does not describe return payloads or multi-account result ordering, so it stops short of a 5.

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?

Despite its length it is front-loaded (read-only framing first), organized into named sections and a category list, and every sentence carries routing or naming information an agent needs. No filler.

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?

Given the router complexity, 29 siblings and nested arguments, the description supplies the missing pieces: the October 2025 Campaign Manager renaming (campaign group vs campaign vs ad set), how to disambiguate user vocabulary, and which tools sit outside this router.

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% and the schema already covers action/accounts/tool_name/arguments. The description still adds real meaning: the free-vs-billed distinction, the all_active sentinel and the 20-account ceiling, and how arguments map to the inner tool's own schema.

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 precisely that this is a read-only router/tool-lookup for LinkedIn Ads and that all mutating operations live in linkedin_ads_write. It even enumerates all 17 read tools by category, so an agent can identify the exact resource set without guessing.

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?

Explicit routing rules: use action="list_tools" or "get_tool_schema" (free) and never guess a tool_name; the one tool not in the router (linkedin_get_campaign_performance) is called by name. It also explains the accounts scoping, so both when-to-use and when-not-to-use are covered.

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