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

Annotations only say it is a non-read-only, non-destructive, non-idempotent write; the description adds the real behavioral payload: a brand may be created as a side effect (plan brand limit applies), links expire in 30 days, the newest of 3 active links is reused with reused: true, Free plan is a no-op returning upgrade info, and anyone with the URL can use it until it is turned off in the dashboard. That is exactly the context annotations cannot carry.

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?

Purpose and audience are front-loaded, and no sentence is pure filler, but it is a single dense paragraph that packs plan gating, link limits, reuse semantics, return fields, and security caveats together. Splitting the return-value and plan-gating details out would make it faster to scan for a tool with only two parameters.

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, and the description compensates by naming the returned fields (url, expires_at, brand, message_for_user, send_to_client) and describing the Free-plan error payload (plan name, price, checkout link). An agent has everything needed to call it and to explain the result.

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 baseline is 3, and the description goes further by explaining the resolution rule: an existing brand with that name is used, otherwise a new brand is created subject to the plan's limit. It does not clarify what happens if both brand_id and brand_name are supplied, or whether brand_id must belong to the caller's account.

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 concrete verb and artifact: 'Creates a private page for one brand, good for 30 days' that a client opens without a PostWire account. The 'for agencies and freelancers posting for clients' framing separates it from sibling link tools (create_connect_link, create_upload_link) that target the account owner's own networks.

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 clear conditions: use it when posting on behalf of a client, supply brand_id or brand_name, and on Free plan nothing is created. Also documents the 3-active-link cap and the reuse behavior instead of erroring. It never explicitly names a sibling alternative for the non-client case, so it stops short of a full when/when-not/alternative statement.

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