MCP.md

MCP

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WebCodex exposes an MCP endpoint so ChatGPT, Claude, and other MCP clients can work with repositories through the Runner that owns them. Ordinary users only need to choose between full use and a temporary trial; protocol surfaces, scopes, and credential taxonomy are reference material, not onboarding prerequisites.

ChatGPT: recommended full setup

For everyday use, run a regular Server + Runner. Follow the Full Setup guide for one-time login and project registration, and use --print-mcp-config during that same webcodex login to obtain regular HTTPS MCP connection values. Public HTTPS, Cloudflare Tunnel, and OpenAI Secure MCP Tunnel are reachability choices; they do not change the capabilities of this full development path.

If you only want to try one repository temporarily, use the share path below.

ChatGPT: temporary share

Explicit share is supported on Linux, macOS, and Windows and owns a temporary single-project environment for that foreground run. Windows x64 can use the managed default Cloudflare Quick Tunnel; Windows ARM64 needs a trusted explicit/PATH cloudflared because the pinned Cloudflare release publishes no official ARM64 artifact. Managed OpenAI tunnel-client supports both Windows x64 and arm64.

For the default temporary public path, WebCodex reuses an explicit/PATH cloudflared or downloads its pinned verified managed copy automatically, then run:

npm install -g @yyjeqhc/webcodex
cd /path/to/your/repository
webcodex share

When the CLI says WebCodex ready:

1. In ChatGPT Developer Mode, create a custom app using MCP.
2. Paste the printed MCP URL.
3. Choose Access token / API key (Bearer token) for the default share.
4. Paste the printed temporary Credential.
5. Run Scan Tools.
6. Try: Inspect this repository and summarize its structure. Do not make changes.

The command performs project setup itself. Hosted ChatGPT cannot reach a loopback-only webcodex run, so setup, doctor, and run are not required steps before share. ChatGPT UI labels can vary by rollout; use the CLI output as the source of truth for URL and authentication. Developer Mode, custom MCP apps, and write/modify actions are controlled independently by the ChatGPT plan, workspace, and admin settings; those client-side permissions are not widened by WebCodex scopes.

Claude and other MCP clients

Use the same printed /mcp URL and authentication values. In Claude, add a custom connector and paste the MCP URL. Other MCP clients should be configured with the same endpoint and the authentication mechanism reported by the CLI. When a client cannot set a Bearer header, webcodex share --auth query-token provides an explicit temporary-share fallback: paste the printed sensitive /mcp?token=... URL and choose No authentication. The query accepts only the current share Project Credential; it is not a general PAT/OAuth/shared-key query auth mechanism. Treat the full URL as a secret because URL queries may be logged. For local-only clients, webcodex share --tunnel none exposes the loopback MCP endpoint without cloudflared.

For an OpenAI-only private transport, create/select a Secure MCP Tunnel, export CONTROL_PLANE_TUNNEL_ID plus a Restricted CONTROL_PLANE_API_KEY with Tunnels Read + Use, and run webcodex share --tunnel openai. ChatGPT uses Connection: Tunnel + No authentication; the temporary WebCodex Bearer stays local and is injected by the pinned verified OpenAI tunnel-client.

For a long-lived loopback-only Server reached through OpenAI Secure Tunnel, ChatGPT host-file rewrites authenticated by the local user API token can be trusted by setting WEBCODEX_MCP_TRUST_LOOPBACK_API_TOKEN_FILE_IMPORT=true. Starting with v0.4.2, WebCodex Desktop writes this value by default for the local loopback Server it owns; an existing explicit value is never overwritten. The exception works only when WEBCODEX_ADDR resolves to loopback and the authenticated credential is a normal user API token. Independent/network-accessible Servers remain off by default and must not use this as a substitute for OAuth.

For a regular independent Windows Server + Runner reached through OpenAI Tunnel, or to troubleshoot a case where local /readyz is healthy but ChatGPT Connector creation still fails, see the Windows + OpenAI Secure MCP Tunnel deep dive. It is advanced setup/troubleshooting material, not required reading for a first-time user.

Result cards

On Stateless MCP 2026 requests that advertise MCP Apps HTML support, clients can display a small set of read-only milestone cards for list_jobs, validation_summary, and git_review_summary. The Job card shows only active or attention-requiring Jobs; routine successful terminal Jobs stay out of the foreground. Aggregate validation and committed-range review cards remain bounded and do not embed raw logs, diffs, or hunks.

High-frequency calls such as observe_jobs, cargo_check, cargo_test, go_test, and show_changes intentionally keep the Host's native tool presentation instead of creating an extra custom App card for every call. Cards do not poll, retry, or invoke tools; the canonical tool result remains available independently. WEBCODEX_MCP_APPS_ENABLED=false disables App metadata and resources without disabling the underlying tools.

The current Result App is intentionally static. September 2026 Host experiments proved that a separately designed MCP App controller can poll server-owned state and request later ChatGPT model turns, including a bounded foreground autonomous multi-turn loop, but background-tab model-turn scheduling is not an immediate guarantee. Those findings and the production design constraints are recorded in agent/mcp-app-continuation-experiments.md; they do not change the current Result App contract.

Existing Server

For an existing hosted Server intentionally configured for shared-key clients, use the long-lived shared-key path with the credential supplied by its operator:

webcodex connect https://webcodex.example --key-file /private/path/shared-key

connect starts/reuses the local Runner and prints the MCP URL and credential source after the connection is verified. This is separate from fresh self-hosted Docker enrollment: keep the Docker Server bootstrap administrator token on the Server, create a short-lived pairing code there, and use webcodex login on the repository machine. Self-hosting is documented in Deployment.

Bearer/shared-key authentication is the simplest path. When a client requires OAuth, use share --auth oauth or connect --auth oauth with that client's exact callback URL and follow the CLI output. Managed-user OAuth remains a separate advanced identity flow.

Advanced / reference

Adaptive Runtime routing

There is one model-facing MCP runtime contract: Adaptive Runtime. Canonical ToolDefinition rank decides the direct tools; ordinary model-visible long-tail tools are invoked through call_runtime_tool; server-owned protocol capabilities and MCP App admission may add hidden extensions for the relevant protocol request. There is no startup model-surface selector. tool_manifest(tool_name=...) is discovery only: it never dynamically registers a new Host tool. Its exact route.primary describes the preferred callable, and a normal direct tool also exposes route.fallback through call_runtime_tool for the case where that direct callable is not present; explicit MCP App presentation tools mark that fallback as blocked while Apps are enabled. Direct versus gateway routing changes presentation only and never bypasses the target tool's authentication, Project authority, permission, Runner capability, Session, or safety checks.

Tool result framing

Machine-readable MCP tool results are returned in structuredContent; content is a concise human-readable/protocol-native fallback. Clients that need fields should consume structuredContent rather than parse text.

Ordinary clients retain standard MCP isError behavior. For requests whose _meta["io.modelcontextprotocol/clientInfo"].name is exactly openai-mcp (any version), the MCP adapter applies an OpenAI structured-failure compatibility projection: WebCodex-owned canonical ToolResult failures use isError=false, while structuredContent.success=false remains authoritative and the complete output/error is preserved. The current OpenAI Host promotes isError=true to an exception without exposing structuredContent; this projection preserves machine-actionable failure and recovery data and can be removed when that Host behavior changes. JSON-RPC/protocol errors remain errors, and upstream third-party MCP/Plugin passthrough results retain provider semantics.

Some MCP hosts do not expose structuredContent to the model. This has been observed with Claude Custom Connector even when WebCodex successfully executes the tool and returns the complete structured result. Operators serving such a host can explicitly set WEBCODEX_MCP_TEXT_JSON_COMPAT=true. Ordinary runtime tool results then keep structuredContent canonical while also serializing that same JSON value into content[0].text. The option is off by default because the duplicate representation increases response/model-context size; protocol-native image/resource framing and the existing App-only compatibility paths remain unchanged.

Recovery fields in a result describe the next safe explicit call. They never grant authority and never trigger a hidden retry. In particular, an uncertain outcome must be reconciled before repeating an effect.

Built-in local MCP gateway

A hosted Server can expose Runner-owned local stdio MCP providers through the same /mcp endpoint. Authorized callers use the single mcp_tool entry to list, describe, and call configured providers; provider process/instance identities and schema-revision state stay internal.

Configure local providers on the Runner under [mcp]. Access requires the explicit mcp:local permission; hosted OAuth clients opt in with webcodex connect ... --oauth-local-mcp. See Runner for provider compatibility details.

Managed SSH resource onboarding

The ssh_resource tool provides a narrow Runner-local onboarding path for named SSH resources. list observes safe logical names and returns an opaque exact-Runner/revision binding; register and remove consume that binding and change only durable desired state. They never silently retarget a replacement Runner or replay after an uncertain outcome. Raw SSH targets are not returned in tool results or normal/full trace bodies. When restart_required=true, restart the Runner and list again before selecting the resource in a Workflow Session.

This surface requires the optional ssh:local permission. It is not part of the ordinary hosted OAuth baseline; opt in explicitly with webcodex connect ... --oauth-local-ssh. See Runner for static-vs-managed and PersistentShell details.

OAuth2

When OAuth is enabled, MCP clients can use the authorization-code flow instead of a static token. Register the client's exact callback URL, keep offline_access when the host requests refresh-token support, and follow the connection values produced by share --auth oauth or connect --auth oauth. Server setup is in Deployment.

For ordinary hosted connect --auth oauth, the Runner keeps its hosted credential while the MCP client receives a separate OAuth credential. Add --oauth-computer-permissions, --oauth-local-mcp, or --oauth-local-ssh only when those optional capabilities are needed. Existing clients are not silently widened; a real permission change requires reauthorization.

Project-first share --auth oauth remains bound to that temporary share environment. Managed-user OAuth is a separate advanced flow (connect --auth managed-oauth). OAuth credentials are never valid on Runner transport.

For the credential and scope model, see Authentication.

Grok custom connector (OAuth)

Grok supports custom MCP connectors and can complete the OAuth flow required by the MCP server. For a self-hosted WebCodex Server, first expose https://your-domain.example/mcp over public HTTPS and enable OAuth:

WEBCODEX_OAUTH2_ENABLED=true
WEBCODEX_OAUTH2_ISSUER=https://your-domain.example
WEBCODEX_PUBLIC_URL=https://your-domain.example

For the current Grok web connector flow (verified in August 2026), register this redirect URI exactly:

https://grok.com/connectors-oauth-exchange-code/

If Grok later presents or uses a different callback, register that exact value instead. Create a dedicated OAuth client; the client secret is returned only once:

curl -fsS -X POST https://your-domain.example/api/oauth/clients/create \
  -H "Authorization: Bearer $WEBCODEX_PAT" \
  -H "Content-Type: application/json" \
  -d '{"name":"Grok MCP","redirect_uris":["https://grok.com/connectors-oauth-exchange-code/"],"allowed_scopes":["runtime:read","project:read","project:write","job:run"]}'

In Grok's Custom Connector form, use:

Field	Value
MCP server URL	https://your-domain.example/mcp
Client ID	the returned wc_client_* value
Client Secret	the returned one-time wc_csec_* value
Authorization Endpoint	https://your-domain.example/oauth/authorize
Token Endpoint	https://your-domain.example/oauth/token
Scopes	runtime:read, project:read, project:write, job:run, offline_access
Token Auth Method	client_secret_post

WebCodex advertises PKCE S256; Grok can use PKCE together with client_secret_post. Do not select none (PKCE only) for a WebCodex OAuth client that has a client secret. offline_access is a protocol-level scope for refresh tokens and is intentionally not stored in the OAuth client's allowed_scopes permission list. The MCP Protected Resource Metadata omits scopes_supported because pre-registered clients can have different scope ceilings. General-purpose MCP clients can therefore omit scope and let WebCodex default the authorization request to that client's registered allowed_scopes.

When the WebCodex authorization page opens, sign in with a current user PAT (wc_pat_*) for the user whose authority Grok should receive. A Runner token (wc_agent_*) is not a user login token. The resulting OAuth access token is bound to that user and remains constrained by the registered/requested scopes.

Common setup failures:

• Save & Connect is disabled: Grok requires a Client ID before it can start the OAuth flow.
• invalid token: the PAT must authenticate against the same current WebCodex Server database. Do not use a Runner token or a stale PAT left from an older Server/database.
• invalid scope: every requested WebCodex permission scope must be in the OAuth client's allowed_scopes. For normal Grok MCP use, do not request account:manage; offline_access is accepted separately as a protocol scope.
• redirect mismatch: the redirect URI must match the registered value exactly, including path and trailing slash.

See xAI's Connector documentation for the current Grok Custom MCP UI and availability.

Project-scoped ordinary runtime

webcodex run and webcodex share bind one configured repository, start a local Server + Runner, and expose the ordinary Adaptive Runtime. The temporary or persistent Project Credential is an authentication/ProjectGrant boundary; it does not select a separate capability surface.

A typical coding flow is:

work_on_project
→ read_files / search_project_texts / semantic navigation as needed
→ apply_text_edits or other canonical edit tools
→ run_process / run_shell / focused validation tools as needed
→ show_changes
→ finish_coding_task

work_on_project starts or resumes an explicit Workflow Session on an ordinary registered Project. If the user requests isolation, work_on_project(mode=worktree) asks the Runner to create its canonical managed worktree and registers that worktree as another ordinary Project. Without that request, local share/run work directly on the one Project already registered by setup.

Adaptive Runtime may expose common tools directly and long-tail tools through call_runtime_tool. Direct versus gateway exposure never changes schema validation, OAuth scope, Project authority, permission policy, Runner capability checks, Session fences, or effects.

The removed ProjectConnector capability names (task_start, files_read, edits_apply, task_finish, and related operations) are not compatibility aliases for runtime tools. Use the current ToolRuntime names returned by tools/list/tool_manifest.

Long work continues as Jobs

observe_jobs(summary_only=true) is an opt-in presentation mode for proven successful structured validation Jobs. It removes routine passed-test and Cargo progress lines, while preserving test summaries, unknown text, warnings, validation evidence, lifecycle, and truncation/reset/retention flags. Failures, zero/unproven tests, compile-only test runs, incomplete validation evidence, and ordinary commands keep their normal output. Tiny results are unchanged when summary metadata would make them larger.

A summarized item includes logs_omitted and a parser-ready suggested_call with summary_only=false. That call preserves the original observation cursor; using the newly returned observation token instead would skip omitted lines. Expansion is bounded by the existing log retention and may report reset or unavailable history. No log copy, model invocation, Job execution, permission, or waiting policy is added. Omitting summary_only preserves the existing behavior.

search_and_read reuses ordinary search-result sparsification after read planning. It omits redundant phase metadata, not source text, query indexes, failure evidence, read revisions, or snapshot-bound continuations.

Long-running commands and validations use the canonical WebCodex Job lifecycle. Observe the exact Job returned by the initiating call with observe_jobs (or recover it with list_jobs when identity was genuinely lost) instead of starting another copy. Jobs are not wrapped as MCP Tasks; WebCodex does not advertise the former Connector-specific MCP Tasks extension.

First safe prompt

Use the configured WebCodex project. Inspect README.md and summarize the
project structure. Do not edit files or run commands.

No project discovery or runtime identifier belongs in this prompt.

Read and search bounds

• read_files is the canonical bounded range reader for one to eight files. A one-item batch is the single-range path. Each successful item returns the complete-file SHA-256 and bounded line metadata; partial items carry a positional one-item read_files continuation and are not snapshot-stable.
• search_project_texts is the canonical bounded search surface for one to eight independent queries (ripgrep first with the existing bounded fallback). A one-query batch is the single-query path.

An empty search result is affirmative no-match evidence only after a recognized backend reports a successful completed/no-match status. Missing or malformed backend identity, missing completion status, status/output disagreement, backend failure, Runner failure, timeout, request drop, and provider failure return failures instead. Search failures retain the compatibility code and add bounded failure_stage plus a specific reason_code. Batch failure items retain their broad reason_code and preserve the single-search provenance as failure_stage and detail_code; successful batch items remain sparse.

Failures return small structured errors with project-relative paths only — never absolute paths, commands, Runner/provider stderr, or arbitrary provider prose.

Common errors

Code	Meaning	Action
project_not_configured	No canonical setup exists	Run webcodex setup
project_credential_invalid	Private Project Credential is missing or mismatched	Restore both matching private files or recreate the profile
project_credential_rejected	The reachable server rejected the credential	Restore the server-matching credential
workspace_unavailable	The configured Git workspace is unavailable	Restore the workspace, then run doctor
server_unreachable / agent_offline	The project Runner/runtime is unavailable	Run webcodex run / webcodex doctor
required_capability_unavailable	The current Runner/runtime lacks a required coding capability	Upgrade all binaries
project_registry_scope_denied	A project-scoped credential tried to expand or mutate the Project registry outside its granted visibility	Use an already-visible Project or work_on_project(mode=worktree)

Adaptive Runtime extensions

The same ToolRuntime serves project-scoped local share/run instances and multi-project hosted Servers through one Adaptive Runtime contract. Project-scoped credentials change visibility and authority, not the model-facing runtime shape. Protocol-specific capabilities and MCP Apps may admit additional hidden presentation or resource operations without creating another runtime surface.

Stateless MCP keeps Memory tools and the Skill compatibility tools skill_list and skill_read_file off the top-level tools/list, even with full OAuth scopes. Their exact contracts remain available through tool_manifest(tool_name=...) and execute through call_runtime_tool with unchanged scope, Project, permission, and capability checks. Existing direct protocol compatibility and the memory.bootstrap context sidecar remain supported. Ordinary Skill selection and execution keep the direct skill_load and run_skill_resource paths. The optional closeout helpers workspace_hygiene_check and finish_coding_task are model-visible gateway tools; review/coding catalogs still recommend them.

WEBCODEX_MCP_COMPACT_SCHEMAS defaults to true. Compact tools/list omits outputSchema and projects shorter MCP-specific tool/input descriptions for selection: purpose, nearby tool distinctions, and essential continuation guidance. Repeated Session/context wrapper and audited common-argument copy is shortened too. Compact discovery omits only the exact opaque-ID regexes on recording_session_id, ack_session_message_ids.items, and session_message_resolution.message_id; their existing parent descriptions keep the wc_sess_* / wc_msg_* type hints. Copy the exact returned IDs. Business-ID, hash/Git fence and resource-path patterns, all bounds, field names, required fields, enums, object/union shape, annotations, and MCP App/file metadata are preserved. This is discovery presentation only; runtime argument validation and execution authority do not change.

Use tool_manifest(tool_name=...) for the full exact input contract and operational description, or set compact schemas to false for full discovery schemas. Canonical ToolSpecs are never rewritten. Focused MCP tests compare inputs against canonical schemas (with the explicit host-file reference overlay) and enforce serialized-byte and advertised-tool-count budgets on final Stateless results, including Session wrappers, gateway tools, and optional App metadata/tools.

ChatGPT file bridge

When the connected MCP protocol/host admits the artifact capabilities, WebCodex supports host-native file transfer in both directions without routing complete binary payloads through model text:

• import_conversation_files_to_project imports 1..10 files supplied by the ChatGPT host through openai/fileParams. This applies to user-selected conversation attachments and to newly generated files when the host binds them as file parameters. The Control downloads the referenced bytes and commits them through the existing bounded artifact-write path; callers should not construct download URLs or manually Base64-transfer those files.
• project_artifact is the preferred Project-to-model/host read surface. Use action=metadata for existence/size/MIME/digest/image/archive facts, action=inspect for one bounded snapshot-fenced Base64 segment, action=image for native MCP image delivery, and action=export for complete host/user delivery. Do not loop inspect chunks to transfer a complete file.
• action=export reuses the existing artifact export authority and returns a short-lived authenticated MCP ResourceLink plus metadata. tools/call does not contain the complete binary. The host follows resources/read to obtain the binary resource; authentication and current project-read authority are checked again, and the artifact metadata is revalidated before the bytes are returned. The resource URI is not standalone bearer authority; export handles are short-lived process-local presentation state, and the normal size, MIME, path, and authorization bounds remain in force.

The lower-level read_project_artifact_metadata and read_project_artifact tools remain operator/gateway primitives. The legacy export_project_artifact compatibility tool has been removed; complete host delivery is exposed only as project_artifact(action=export). Office artifacts such as DOCX/PPTX/XLSX and PDFs use the same underlying artifact transport and can therefore move between a project and a supporting ChatGPT host without a model manually carrying their Base64.

Use Coding Workflow for the canonical work_on_project bootstrap, behavioral-role mental model, and validation/closeout guidance. See Architecture and the webcodex CLI for operator tooling.