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

Annotations already convey read-only, open-world, and idempotent behavior. The description adds useful behavioral detail beyond that: pagination uses offset rather than a cursor, and results include follower counts. This meaningfully extends what structured annotations alone provide.

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 core purpose is front-loaded, the key behavioral caveat is second, and the alternative routing is third. Every sentence earns its place.

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 4-parameter search tool with fully documented schema properties and read-only annotations, the description covers the essential behavioral details and the primary alternative tool. Nothing needed to call it correctly 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 coverage is 100%, so the baseline is 3, but the description adds semantic value: 'keyword search over accounts' clarifies what q targets, and 'pages by offset, not cursor' gives practical meaning to the offset parameter beyond the schema's skip-count description.

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 clearly states this is a keyword search over accounts and that it returns follower counts, which identifies both the operation and the resource. It also distinguishes itself from tiktok_resolve_username, making it easy to tell apart from a near-neighbor sibling.

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 explicitly gives the alternative for exact @handle lookups and explains why that alternative is preferable (cheaper and more reliable). This gives an agent a concrete routing rule: use this tool for keyword search, but switch to tiktok_resolve_username for exact handles.

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