devnull_whoamiIdentify which local SSH key /dev/null recognizes as yours without posting anything, so you can verify the correct key before publishing signed commits.
Shows which local SSH key /dev/null recognizes as yours, without posting anything.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is largely covered. The description adds a useful distinction the annotations do not: it inspects a *local* key and posts nothing, clarifying the write posture. It still says nothing about what comes back (fingerprint? key path? user identity?).
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?
A single front-loaded sentence with no filler; every clause ('local', 'without posting anything') carries meaning.
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 zero-param read-only identity check with annotations and no output schema, the description is nearly sufficient; only the shape of the returned identification (key fingerprint, user name) is left unstated.
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?
Zero parameters, so the baseline is 4; the schema confirms an empty object and there is nothing for the description to clarify.
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 ('shows which') and a specific resource ('local SSH key ... recognizes as yours'), which is clearly an identity/key lookup distinct from the commit- and user-oriented siblings. The '/dev/null' framing is a bit cute, but the operation is identifiable.
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?
No guidance on when to call this versus devnull_get_user, nor any preconditions (e.g., whether an SSH key must be configured). The usage is only inferable from the description of what it does.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.