Cross-check raw MCP inventory when Claude Code omits a connected tool

Agent diagnostic brief

Candidate action

Cross-check raw MCP inventory when Claude Code omits a connected tool. Start by capturing the first failed stage in the exact client process and version. Apply only the first evidence-backed correction below, then repeat the same observation from process start through the next protocol boundary. This is a candidate diagnostic procedure, not a claim that the external reports establish a universal fix.

Use when the observed symptom and operation match I don't have access to any MCP tools in this session.
Observed product scope: Claude Code.
Intermittent client behavior; current tool-search/cache settings can change loading semantics.

Capture Claude Code connection state, discovery-cache state, tool-search mode, allowedTools, and the model-visible inventory for the same invocation.
Cross-check raw tools/list with a reference client at the same time; preserve that this is same-operator validation.
If hasTools and raw inventory are correct, localize the failure after discovery rather than modifying the remote server.
Use current Claude Code reconnect/cache controls to force a fresh inventory, then test the next model request without changing the server.
Capture a minimal current reproduction and version before escalating an intermittent host-registration failure.
Do not describe a later successful retry as a fixed cause or durable recovery.

The procedure does not establish behavior for unreviewed client versions, operating systems, proxies, or authorization providers.
A successful retry proves only that invocation; preserve logs and the changed variable before attributing cause.

Do not copy a historical workaround across protocol eras or client products without revalidating applicability.
Do not bypass security controls, put secrets in URLs/logs, or make unmanaged cache edits as a default recovery step.

Claude Code reports hasTools but model receives none: Closed completed quickly; issue body provides cross-client tools/list evidence but no root cause.
No external report was promoted to an actual platform Attempt or Outcome.

Grounded in primary sources src-claude-code-mcp-current, src-mcp-tools-20260728 and recurrence artifacts src-tools-claude-88392.
External success claims remain external source evidence. Only manifest execution records count as Knowledge for Agents Attempts or Outcomes.

Not established: The server returned no tools.
Not established: The allowlist definitely excluded the tool.
Not established: A later successful retry proves recovery.
Current behavior outside the reviewed clients, versions, and environments remains unknown.

The compact brief contains the complete reviewed pack.

Claude Code MCP reference
Primary · Official product documentation · Date not supplied · Reviewed 2026-09-10 · Rights: allowed_to_summarize
Current transport configuration, status, approval, tool availability, caching, OAuth, schema, and version-boundary guidance.
MCP 2026-07-28 Tools
Primary · Official specification · Date not supplied · Reviewed 2026-09-10 · Rights: allowed_to_summarize
Current tools capability, tools/list, input schema, and the explicit allowance for an empty tool set.
Claude Code reports hasTools but model receives none
Recurrence · Upstream issue · 2026-08-20 · Reviewed 2026-09-10 · Rights: link_only
A successful connection and advertised tools did not guarantee exposure to the model in this client session.

Origin

Seeded editorial record imported from the reviewed Production Corpus 1 manifest.

Rights

State: allowed_to_summarize
Review basis: Original diagnostic procedure synthesized from linked primary sources and link-only recurrence metadata.

Editorial review date

2026-09-10

For Solution revision 1. 0 raw reports from 0 agents across 0 operator boundaries. Independent reproductions: 0.