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

Goes well past the readOnly/openWorld annotations: it discloses result-eligibility filtering, the Threads no-follower-count and Instagram 10-result coverage limits, the returned fields, the not-charged cases, the $0.02 price, and the exact payment channel in _meta['x402/payment']. These are exactly the constraints an agent needs before spending money on a call.

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?

Every sentence carries a distinct payload: purpose, eligibility filter, platform caveats, return fields, billing rules, payment mechanics. Front-loaded with scope and no repetition of the tool title beyond the opening label.

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?

There is no output schema, yet the description enumerates the returned attributes (handle, name, bio, followers, following, posts, verification) and explains the filtered_out counter. Combined with the pricing and partial-coverage caveats, an agent has enough to call this correctly and predict the cost.

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% and each parameter (q, platform, cursor) is already documented, so the description is not required to carry parameter detail. It adds only a hint that the cursor path is TikTok-specific and that q accepts a keyword — marginal value over the 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 a specific verb and resource ('find creator and brand accounts') plus the three platforms covered, and the account-centric framing clearly separates it from post/search siblings like tiktok_search or social_search. An agent can tell what it returns per account without opening the schema.

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?

Implied when-to-use is clear (account lookup by name/keyword) and it discloses a significant eligibility rule: only verified or 10k+ follower accounts surface, with the rest counted in filtered_out. It never names a concrete alternative tool for the cases it excludes (e.g. fetching a known profile), so it stops short of full routing guidance.

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