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

Annotations already cover readOnly, idempotent, and closed-world behavior, so the description needn't restate safety. It does add two things the annotations cannot convey: the tool is pay-per-call (5 sats or US$0.005 USDC), which implies an L402/x402 payment handshake, and coverage is limited to the mempool plus the last 6 blocks. It stops short of saying what happens for older transactions or failed lookups.

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, both earning their place: purpose with return-state detail first, pricing second. The parenthetical field list is dense but informative. The nested clauses in the first sentence make it slightly harder to scan, but nothing is redundant.

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?

With no output schema, the description carries the burden of describing returns, and it does so by enumerating mempool fields (fee rate, age, RBF, estimated blocks) and confirmations for confirmed transactions. What is missing is the boundary case: whether a tx older than 6 blocks returns an error, an empty result, or falls back to another tool.

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%, so all three parameters, including the l402 token format and the pay_with enum, are already documented in the schema. The description reinforces the payment context that makes l402/pay_with meaningful but adds no new syntax or format detail beyond it. Baseline 3 applies.

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 names a specific resource and scope: the status of exactly one Bitcoin transaction, 'as seen by this node', with the two possible outcome states (mempool vs confirmed in the last 6 blocks) spelled out. This cleanly separates it from siblings such as bitcoin_decode_transaction (which parses a raw tx) or bitcoin_transaction_eta (which projects timing).

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?

Usage is implied rather than stated: you call it when you have a txid and want to know its current state. There is no explicit when-to-use guidance against alternatives like bitcoin_transaction_eta or bitcoin_decode_transaction, nor any statement of when not to use it (for example, for transactions confirmed more than 6 blocks ago).

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