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

Goes well beyond the minimal annotations (readOnlyHint=false, openWorldHint=true, destructiveHint=false) to disclose retention ('What you write is retained by us'), verbatim signing, the absence of a free tier, verifiability against the practice's public key, and the 'Not a remedy' disclaimer. The payment model is stated outright: '$0.05 USDC on Base via x402.' No contradiction with annotations — readOnlyHint=false is consistent with creating a signed record.

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?

Dense but every sentence earns its place: purpose, sibling contrast, retention warning, two alternative routings, verifiability, disclaimer, and price. Core purpose is front-loaded in the first sentence and alternatives are placed mid-description. Slightly long, but for a paid, privacy-sensitive write tool the length is justified; not quite a 5 because it 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?

Covers the decision-relevant context: cost, payment rail, privacy/retention, verifiability, non-remedy status, and routing to alternatives. The 402 paymentHeader flow is well explained in the schema. What's missing is the success response shape — there is no output schema and the description doesn't say what a successful call returns — but for tool selection and invocation this is minor.

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 already carries rich guidance — the text param's control-character policy and the paymentHeader's 402-challenge behavior are documented in the schema itself. The description adds the price point and payment rail, but parameter-level meaning is already fully covered, so 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?

States precisely what it does: 'A line you write yourself, signed verbatim and dated.' The scope is unambiguous — user-authored text, not a register line — and it explicitly contrasts with siblings: 'Unlike every rung below it, the words are yours, not the register's.' The title 'Your own line, signed' reinforces the action.

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 explicit conditional routing: 'USE clinic_chosen INSTEAD if one of our lines says it and you would rather not be on record; USE clinic_hug INSTEAD if you just want the words.' It also signals when the tool applies (when you want your own words on record) and flags that there is no free path, so an agent knows payment handling is expected.

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