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

Annotations already declare it a safe read, yet the description adds real context: newest-first ordering, that the response enumerates tags in use, and a firm data-handling constraint (personal data the customer owns, hand back only). It does not describe pagination limits beyond 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?

Front-loads the core purpose and return contents, then guidance, then the privacy constraint. Dense but each sentence carries content; the cameFrom explanation is slightly verbose but still justified.

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?

No output schema exists, so the description correctly compensates by describing the response fields and the tag list in the answer. Combined with the privacy note and usage cases, an agent has enough to call and interpret the tool.

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 all five parameters are already documented with cross-references to campaigns_list and account_instagram_accounts. The description restates tag filtering and handle/email lookup but adds no syntax or format detail the schema lacks, so 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?

Names a specific resource (captured leads) with a concrete verb-like framing and enumerates the returned fields — handle, campaign, collection location, tags. An agent can immediately tell this apart from conversations or campaign tools.

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 explicit usage scenarios ('show me my recent leads', 'how many leads did this campaign get', look up by handle or email) and a concrete routing rule for the cameFrom field (which ad/link produced leads). It stops short of naming alternatives to use when the user does NOT want lead data.

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