GPTsAppEarliest supported layer
Rules distinguish availability, discovery, parsing, configuration, dependency, connection, authentication, registration, exposure, activation, authorization, execution, and persistence.
Codex capability diagnosis
Why is this MCP server not working in Codex?
Paste the first MCP startup, initialize, auth, tool-list, or invocation error—not an entire log.
Local redaction. Save only by choice.
Diagnosis workspace
Not checkedEvidence in.
One useful next step.
Your result appears here after you review and submit the sanitized evidence.
- First supported boundary
- Waiting for evidence
- Next check
- Not selected yet
- Private report
- Not created
Worked example — not your diagnosis Connection A compact output computed by the current deterministic ruleset. CONNECTED
Example evidence
The configured MCP server process starts, then initialization failed: transport closed before the handshake completed. This is a new install in Codex CLI.
Result
Connection · CONNECTED
The earliest supported failure is connection: the host cannot complete a stable transport or initialization handshake with the capability provider.
Why this boundary
The evidence names refusal, timeout, initialization failure, or early transport closure before authentication or tool registration is evidenced.
Next safe check
Observe whether the MCP server reaches connected/authenticated status
Confirm startup and handshake before changing OAuth, session exposure, or tool permissions.
Method and limits
A capability chain, not an AI guess
- Redacted on this device
- Inspectable deterministic ruleset · 15 checkpoints
- Saved only when you choose
Deterministic rules over your redacted evidence. What the tool cannot support, it declines to claim.
Evidence before verdict
A rule must meet a deterministic threshold. Conflicting or incomplete evidence becomes partial or unknown; it is not converted into a confident root cause.
No unknown execution
The site does not install capabilities, execute packages, contact private endpoints, edit configuration, or ask for credentials.
Private by explicit choice
A diagnosis is stateless by default. Saved reports use random URLs, expire after seven days, can be deleted immediately, and are excluded from indexing.