Gopher & Gemini MCP Server

Inspect Gemini client certificates

gemini_client_cert_list

Read-only

List the Gemini client certificate identities held for each scope, showing fingerprints and expiration, to verify pseudonymous identities or troubleshoot certificate-not-valid (status 62) responses.

Instructions

List the Gemini client certificates (identities) this server holds.

A client certificate is a persistent pseudonymous identity, not a login. While one exists for a scope, every request within that scope carries it automatically, so the capsule can link those visits to each other for as long as the certificate lasts. This tool reports which scopes have such an identity; it never creates, changes or removes one, and it never reveals a private key or where one is stored.

This is the client half: OUR identity, the certificate this server presents to a capsule. The certificate a capsule presents to US is the separate TOFU trust store, read with gemini_trust_list and changed with gemini_trust_update. The two stores are unrelated, and changing one never affects the other.

Use it before gemini_client_cert_update: it is the source of the fingerprint that tool requires before it will destroy an identity, and an entry reported as expired explains a capsule that keeps answering status 62 (certificate not valid).

Returns: The stored certificates matching the request, each with the scope URL to pass back to gemini_client_cert_update, its host, port and path scope, SHA-256 fingerprint, validity window and whether it has expired.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`host`	No	Hostname to report on, e.g. astrobotany.mozz.us . Omit to list every scope holding an identity -- which is in effect the list of capsules this user has an account or pseudonym on, so name the host you are actually asking about unless the user wants the whole store.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Addedv0.10.2Sep 8, 2026

TDQS

A5/5.0

Behavior5/5

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

Annotations declare readOnlyHint=true; the description goes further by stating it never creates, changes, or removes identities, never reveals private keys, and explains the identity behavior (automatic per-scope carrying, persistent pseudonymous nature). This adds meaningful context beyond the structured annotations with no contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core action and then organized into small purposeful paragraphs. The length is justified because it prevents confusion with closely related tools and communicates safety-relevant behavior; no sentence is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The definition covers what the tool returns, how to use it with gemini_client_cert_update, how to interpret expired entries, and how it relates to the trust store siblings. For a simple one-parameter read-only tool with an output schema, nothing needed for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Although the single host parameter is already described in the schema, the description enriches it by explaining that omitting it lists every scope holding an identity and advising the agent to name the host actually being asked about. This is practical decision support beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description opens with a specific verb+resource: 'List the Gemini client certificates (identities) this server holds.' It distinguishes the client identity store from the TOFU trust store and from gemini_client_cert_update, so an agent can tell it apart from siblings without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit when-to-use guidance: run before gemini_client_cert_update to obtain the required fingerprint, and use expired entries to diagnose status 62. It also names the sibling for the opposite trust store, preventing confusion.

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

Deploy Server