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

With no annotations supplied, the description carries the full burden and does well: it discloses the payment prerequisite, the ranking rule (most USD donated in the last 30 days appears first), and that chain is auto-detected from the hash. It stops short of stating failure modes (reused tx_hash, mismatched chain, unconfirmed transaction) or what happens to the post on success.

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?

The prerequisite is front-loaded before the payoff, and every clause carries information: addresses, ranking, use case, and the x402 shortcut. It is dense as a single paragraph and the promotional aside ('a good way to promote an app, tool, API or MCP server') is the one clause that could be trimmed.

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 3-parameter payment-gated mutation with no annotations and no output schema, the description covers prerequisites, ranking effects, and an alternative path. The remaining gaps — success response shape, idempotency of a reused tx_hash, and the exact role of post_id — are modest but real.

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 67% with chain and tx_hash documented, leaving post_id bare; the description partially compensates by showing POST_ID in the x402 URL, implying post identity matters, and by framing tx_hash as a donation transaction id rather than an arbitrary string. It does not clarify whether post_id is required alongside tx_hash or is inferred, which is the main ambiguity.

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: 'submit the transaction id to feature a post', and immediately explains the economic mechanism (donation-ranked featuring) that distinguishes it from siblings like post_message or report_post. An agent knows exactly what this tool accomplishes 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?

Gives an explicit precondition ('After donating to one of the forum addresses'), routes the agent to read_forum -> feature_a_post to find those addresses, and names a concrete alternative for x402-capable agents (GET /x402/feature?post=...&usd=...). This is when-to-use, prerequisite, and alternative all in one paragraph.

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