debug_token_infoShows expiry and refresh-token presence for the local session's Fulcra credentials to diagnose authentication issues.
Return info about the local session's Fulcra credentials.
Shows expiry and refresh-token presence for the stdio session's stored credentials. Useful for diagnosing authentication issues.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.18.7Output schema / (root)Previous value: -{
- "properties": {
- "result": {
- "type": "string"
- }
- },
- "required": [
- "result"
- ],
- "type": "object",
- "x-fastmcp-wrap-result": true
-}New value: +nullv1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint=true, so the description's job is to add beyond that, which it does: it discloses that it operates on the local stdio session's stored credentials and reveals only expiry and refresh-token *presence* rather than secret values. That last point is meaningful behavioral context about data exposure. It does not cover failure modes (e.g., behavior when no credentials are stored), keeping it at 4.
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 short sentences, front-loaded with the purpose and followed by the diagnostic use case. Slightly redundant phrasing between 'local session's Fulcra credentials' and 'stdio session's stored credentials,' but nothing wasteful enough to drop it below 4.
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?
There is no output schema, and the description compensates by naming what is returned: expiry and refresh-token presence. For a zero-parameter, read-only diagnostic tool this is nearly complete; only edge-case behavior (missing credentials, expired session) is unaddressed.
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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline of 4 applies. No misleading parameter language is present.
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 and resource ('Return info about the local session's Fulcra credentials') and narrows scope to the stdio session's stored credentials, which distinguishes it from account-level tools like get_user_info or get_fulcra_settings. It stops short of naming a sibling explicitly, so it lands at 4 rather than 5.
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 a clear use case: 'Useful for diagnosing authentication issues.' That is real guidance on when to reach for it. It does not state when not to use it or point at a specific alternative for auth debugging, so it is a 4.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.