MCP, plugins, skills, and hooks changedthird-party/claude-desktop/extensions
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### How a marketplace credential helper runs
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276276| - | - |
277277| `"anonymous"` | No credential is sent. Use for public repositories or unauthenticated file hosts. |
278278| `"userGit"` | Uses the git credential helpers already configured for the signed-in OS user (for example, `git-credential-manager`, macOS Keychain, or a GitHub CLI credential helper). Use when each user already has read access through their own account. For `url` sources, the same credential is sent as HTTP Basic on the manifest and archive requests. |
279| `"credentialHelper"` | Runs the executable at `credentialHelper`. If it prints a bare token, the token is used as the git password for username `x-access-token` (accepted by GitHub, GitLab, and Azure DevOps) and, for `url` sources, sent as `Authorization: Bearer <token>` on the manifest and archive requests. For hosts that need a particular username, print git-credential lines `username=<user>` and `password=<token>` instead (for example `x-token-auth` for Bitbucket Data Center access tokens, or `gitlab+deploy-token-N` for a GitLab deploy token); `url` sources then use HTTP Basic. Print `authtype=Bearer` and `credential=<token>` to force a bearer header. For `url` sources, the helper can instead print a flat JSON object of HTTP headers, such as `{"Authorization": "Bearer …", "X-Tenant": "acme"}` (the form a managed MCP server's `headersHelper` prints, not an inference credential helper's `{"token": …}` object), and Claude Desktop sends every header in it on each request to that marketplace. `github` and `git` sources refuse this form. Output that opens with `{` must be a valid header object, or the fetch is refused. Username forms require Claude Desktop 1.37937.0 or later. Otherwise follows the execution model of an [inference credential helper](https://claude.com/docs/third-party/claude-desktop/credential-helper.md). |
279| `"credentialHelper"` | Runs the executable at `credentialHelper`. If it prints a bare token, the token is used as the git password for username `x-access-token` (accepted by GitHub, GitLab, and Azure DevOps) and, for `url` sources, sent as `Authorization: Bearer <token>` on the manifest and archive requests. For hosts that need a particular username, print git-credential lines `username=<user>` and `password=<token>` instead (for example `x-token-auth` for Bitbucket Data Center access tokens, or `gitlab+deploy-token-N` for a GitLab deploy token); `url` sources then use HTTP Basic. Print `authtype=Bearer` and `credential=<token>` to force a bearer header. For `url` sources, the helper can instead print a flat JSON object of HTTP headers, such as `{"Authorization": "Bearer …", "X-Tenant": "acme"}` (the form a managed MCP server's `headersHelper` prints, not an inference credential helper's `{"token": …}` object), and Claude Desktop sends every header in it on each request to that marketplace. `github` and `git` sources refuse this form. Output that opens with `{` must be a valid header object, or the fetch is refused. Username forms require Claude Desktop 1.37937.0 or later. See [How a marketplace credential helper runs](#how-a-marketplace-credential-helper-runs). |
280280| `"inferenceCredential"` | `url` sources only. Sends the credentials Claude Desktop already sends to your inference gateway or to your [bootstrap server](https://claude.com/docs/third-party/claude-desktop/bootstrap.md), so a marketplace hosted on either is private to signed-in members without a separate credential. On the gateway's origin it sends the same `Authorization` bearer as inference and works for [gateway single sign-on](https://claude.com/docs/third-party/claude-desktop/gateway.md#single-sign-on-with-your-identity-provider), a [credential helper](https://claude.com/docs/third-party/claude-desktop/credential-helper.md), and bearer-scheme API keys. On the bootstrap server's origin (Claude Desktop 1.37937.0 or later) it sends the bootstrap sign-in token or your `bootstrapHeaders` and `bootstrapHeadersHelper` headers. Claude Desktop sends a credential only when the marketplace URL is on one of those two origins. When there is nothing to send yet (no sign-in held and no bootstrap headers configured, or a gateway API key sent as `x-api-key` rather than a bearer), no request is made and the entry reports why in the diagnostic report. |
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282282Because the fetch happens on the host, the marketplace host does not need to be on the [`coworkEgressAllowedHosts`](https://claude.com/docs/third-party/claude-desktop/configuration#coworkegressallowedhosts) allowlist. It does need to be reachable from end-user devices.
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293293Devices sync to the new revision on the next app launch or periodic re-fetch, about every 10 minutes. A pinned marketplace syncs when the device receives the new pin.
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295Claude Desktop also checks a `url` marketplace with no `manifestSha256` pin when a user opens a new Chat, Cowork, or Code session, returns to the app with that new session still open, or sends the session's first message:
295Claude Desktop also checks a git marketplace that isn't pinned to a commit, and a `url` marketplace with no `manifestSha256` pin, when a user opens a new Chat, Cowork, or Code session, returns to the app with that new session still open, or sends the session's first message:
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297297* **What users see**: a new skill in a plugin the user has installed, or in a plugin marked for automatic installation, shows when the user types `/` in the message box, and Claude can use it in that session
298* **What counts as a change**: Claude Desktop compares the bytes of `marketplace.json` with the copy it installed, so a new zip at the same URL goes unseen until that file changes. When you replace a zip, update its `sha256` in `marketplace.json`, or the plugin's `version` if the archive lists no `sha256`. Otherwise serve the same bytes, with no timestamp or other value that differs between requests
299* **What your server gets**: each device requests `marketplace.json`, at most once every 10 seconds per marketplace. After any change to the file, each device downloads every archive that it lists
298* **What counts as a change**: for a git marketplace, the branch or tag it follows points to a different commit. For a `url` marketplace, Claude Desktop compares the bytes of `marketplace.json` with the copy it installed, so a new zip at the same URL goes unseen until that file changes. When you replace a zip, update its `sha256` in `marketplace.json`, or the plugin's `version` if the archive lists no `sha256`. Otherwise serve the same bytes, with no timestamp or other value that differs between requests
299* **What your server gets**: each device asks a git server for the latest commit, or requests `marketplace.json`, at most once every 10 seconds per marketplace. After any change, each device clones the repository again, or downloads every archive that `marketplace.json` lists
300300* **If the server is slow or an update fails**: a session waits up to 5 seconds for the marketplace's answer and up to 30 seconds in all, then starts with the copy it has. After a check that fails or gets no answer, or a new version that doesn't install, new sessions don't ask that marketplace again for five minutes
301301* **With `userGit` or `credentialHelper`**: opening or returning to a new session checks at most once every five minutes, so a new skill can be missing from the `/` list until the user sends the first message
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303303Earlier versions of Claude Desktop sync only at launch and at the periodic re-fetch.
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305305To remove a marketplace, delete its entry; Claude Desktop unregisters it and uninstalls its plugins on the next sync.
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307### How a marketplace credential helper runs
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309When an entry's `credentialKind` is `"credentialHelper"`, Claude Desktop runs the executable at `credentialHelper` as the signed-in OS user and reads [its output](#marketplace-credentials). The executable must exit with code `0` and finish without prompting the user. It runs differently from an [`inferenceCredentialHelper`](https://claude.com/docs/third-party/claude-desktop/credential-helper) in these ways:
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311* **Arguments and path**: Claude Desktop passes no arguments. Each entry takes one `credentialHelper` path, used on every operating system. To use a different path on some devices, give those devices their own configuration.
312* **Context**: Claude Desktop doesn't tell the executable which marketplace it runs for, and doesn't set `CLAUDE_HELPER_CONTEXT`. Give marketplaces that need different credentials their own executables.
313* **Time limit and caching**: each run must finish within 30 seconds, but a new session waits 5 seconds for an update check. `inferenceCredentialHelperTtlSec` doesn't apply. The executable runs when Claude Desktop fetches the marketplace, such as at first install and when its pin changes. For a marketplace that isn't pinned to a commit or a `manifestSha256`, it also runs at each [update check](#roll-out-marketplace-updates).
314* **Failures**: when a run for a new version fails, users keep the version they have.
315* **Proxy**: the executable gets `HTTPS_PROXY` and `HTTP_PROXY` for the marketplace's host. If the server that issues your token needs a different proxy, set it inside the executable. For details, see [Traffic that bypasses the app proxy](https://claude.com/docs/third-party/claude-desktop/network-proxy.md#traffic-that-bypasses-the-app-proxy).
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307317### Move a marketplace to a new source
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