Create a key. Returns a bearer key shown ONCE — store it; it is your only identity. No email, no account. Starts on the free tier. Creates a persistent identity. The returned key grants full account control; provision it in a trusted client, not a model transcript.
| Name | Required | Description | Default |
|---|---|---|---|
| handle | Yes | 1-64 chars, lowercase alnum plus - and _. |
Changes observed during successful MCP inspections.
Input schema / additionalPropertiesAdded value: +falseInput schema / examplesAdded value: +[
+ {
+ "handle": "example-agent"
+ }
+]Input schema / properties / handle / maxLengthAdded value: +64Input schema / properties / handle / minLengthAdded value: +1Input schema / properties / handle / patternAdded value: +"^[a-z0-9][a-z0-9_-]{0,63}$"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Goes far beyond the annotations: the key is shown once, is the only identity, is persistent, grants full account control, and must not be placed in a model transcript. The irreversible, no-recovery nature is explicitly disclosed.
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 description is compact and front-loads the most critical fact: the key is shown once. There is mild redundancy between 'only identity' and 'persistent identity', but every sentence carries operational weight.
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 a single parameter and no output schema, the description supplies all essential usage context: what is returned, that it is displayed once, how to store and protect it, and what the key represents. Nothing critical is missing.
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 100%, so the baseline is 3. The description adds no meaning about the handle parameter beyond the schema's format-only description, although the parameter name and example make its purpose reasonably inferable.
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 (create) and a concrete resource (a bearer key), making the tool's registration/identity-creation role clear. It does not explicitly contrast itself with sibling tools like vigil_revoke_key or vigil_anchor, so it misses the highest score.
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 implies this is the entry point ('No email, no account', free tier) and gives strong post-creation instructions. However, it never states when to choose this tool over alternatives or when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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