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

Annotations already signal mutation and non-idempotency (readOnlyHint=false, idempotentHint=false). The description adds meaningful behavioral nuance: the digest is sent to external OpenTimestamps calendars and 'submission is not verified Bitcoin confirmation,' warning that calling this does not guarantee a confirmed result. This goes beyond what annotations alone provide.

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 compact sentences carry all the necessary information: the first identifies the action and scheduling context, the second exposes the main limitation. There is no filler, repetition, or redundant restatement of schema fields.

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 triggering action with one optional deprecated parameter, the description covers the purpose, scheduling, external effect, and the confidence caveat. The only notable gap is that no output schema exists and the description doesn't state what the call returns, such as a receipt or status.

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?

The only parameter, vigil_key, is fully documented in the schema with deprecation and authentication guidance, so the description doesn't need to repeat it. Since schema description coverage is 100%, the baseline of 3 is appropriate; the description adds no parameter-level detail but none is necessary.

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 precise action—anchoring the current chain head to OpenTimestamps on demand—rather than a vague verb. The parenthetical clearly distinguishes it from the automatic periodic anchoring, so an agent can tell exactly what this tool uniquely does.

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 explains the trigger condition: use this when an anchor is needed before the next automatic anchor, which happens every few hours regardless. It doesn't explicitly name sibling tools or exclusion cases, but the scheduling context makes the when-to-use decision reasonably clear.

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