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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), yet the description adds two genuinely useful behavioral facts not in structured data: an external cost ($0.01 USDC per call via x402) and the returned artifact (.ots proof file) with its later-verification purpose. It stops short of noting rate limits, confirmation latency, or the calendar/blockchain dependency.

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 purpose and mechanism, then the outcome, then the cost — no wasted sentences. Slightly dense but every clause adds information a caller needs.

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?

Return value is adequately described (the .ots proof file) even without an output schema, but for a 4-param tool at 0% schema coverage the description should clarify input selection and mutual exclusivity. It also omits prerequisites such as the x402 payment flow setup, which sibling tools like x402_check exist for.

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 0% and none of the four params are required, so the description carries the burden. It hints at text, file and URL inputs (mapping loosely to text, content_base64, url) but never explains sha256 or how the four inputs relate (e.g. mutual exclusivity, precedence), leaving real ambiguity about how to call it.

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 (anchor) and resource (SHA-256 of text/file/URL) plus the mechanism (OpenTimestamps calendars / Bitcoin blockchain) and the deliverable (.ots proof file). This is instantly distinguishable from siblings like btc_tx or x402_check, and an agent can tell what the tool produces 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?

The description gives the scenario ('so anyone can later verify the data existed at that time'), which implies when to reach for it, but names no alternatives or exclusions among the many sibling tools (e.g. since, time, btc_tx) and gives no guidance on which parameter to supply. Usage is inferable rather than stated.

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