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

Annotations already declare openWorldHint=true and destructiveHint=true, and the description adds meaningful context: the message reaches the real customer, a note is appended to the contract's history, the customer pays on the checkout page, and no charge occurs here. It does not state failure modes (what happens to an unaccepted contract, or whether a resend duplicates the history note), which keeps it below 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?

Front-loaded with the action and the [publish] marker, then prerequisites, then side effects. The parenthetical id-or-uuid enumerations are dense but each earns its place; a couple of clauses could be tightened.

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 an 11-parameter, no-output-schema mutation tool with rich annotations, the description covers what the agent needs: eligibility, routing inputs, platform vocabulary, message composition, and the real-world side effect. Only the unexplained required 'provider' keeps this from being flawless, and that is a schema-side omission rather than a description failure.

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 0%, so the description must carry the load, and it does for most parameters: contract_id/contract_uuid, price and website by id or uuid, platform = wp|ig|fb|tw, chat_id format derived from list_chats, and the message body. The notable gap is 'provider', a required parameter that is never explained anywhere.

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?

Specific verb + resource + scope: sends the payment link of an ACCEPTED contract to the customer inside their conversation. The bracketed [publish] tag and the explicit "nothing is charged here" separate it cleanly from get_payment_link (retrieval) and from payment/checkout siblings.

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 a real precondition (contract must be ACCEPTED) and tells the agent where chat_id comes from (list_chats). It does not explicitly name the alternative to use when the contract is not accepted or when the link should only be fetched rather than sent, so when-not guidance is only implied.

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