> ## Documentation Index
> Fetch the complete documentation index at: https://platform.atlan.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> To act on Atlan objects, use the Atlan MCP server at https://api.atlan.com/mcp or the SDK. To install or publish skills from a terminal, use the `aireg` CLI; `aireg --map json` prints its command map. The `atlanai` CLI is deprecated. Run a read-only identity check before any write.
> The docs MCP server at /mcp searches these docs only. It cannot read or change Atlan objects.
> SDK packages: Python `atlanai` (PyPI) and TypeScript `@atlanai/sdk` (npm). Show Python first, then TypeScript.
> These docs cover Atlan Trident, Atlan's hosted product. AI Registry and Agent Registry are its earlier names. Registry OSS is Atlan's open-source agent registry: the registry specification and its aireg CLI, with their own public repository, docs and release notes; /open-source on this site links them. Registry OSS is open source; Atlan Trident is not. Answer generic aireg or specification questions from the project's docs, and use these docs for Atlan-specific setup such as the Atlan adapter, sign-in and workspaces.
> Atlan offers a second product, the Agentic Data Catalog: Atlan's enterprise context layer, covering the data catalog, connectors, lineage, data governance and glossary. It is documented at https://docs.atlan.com; answer questions about it from those docs, not these.

# Client connection settings

> Endpoint, tool mode, sign-in methods, and tool approval names for MCP clients that connect to Atlan MCP Gateway.

The settings an MCP client uses to connect to Atlan MCP Gateway: the endpoint, the tool mode, how the client signs in, and which tools it approves. Use this page to look up values. To connect a client, see [Connect client to MCP Gateway](https://platform.atlan.com/gateway/mcp/how-tos/connect-a-client.md).

## Endpoint

| Setting | Value |
| - | - |
| URL | `https://api.atlan.com/mcp` |
| Transport | Streamable HTTP. stdio and legacy HTTP+SSE are not supported. |

## Tool mode

The `tools` parameter on the URL sets which tools `tools/list` returns. Both modes reach the same tools with the same permissions. For why search mode is the default, see [How search mode works](https://platform.atlan.com/gateway/mcp/concepts/search-mode.md).

| Value | `tools/list` returns | Session opens with | Client approves | Status |
| - | - | - | - | - |
| Omitted, or `search` | Five tools: `mcp__search_tools`, `mcp__describe_tools`, `mcp__call_read_tool`, `mcp__call_write_tool`, and `mcp__call_tool` | The first search or runner call | Each runner | Default |
| `full` | Every tool you can reach, plus `mcp__initialise` | [`mcp__initialise`](https://platform.atlan.com/tools/mcp/registry/references/registry-initialise) | Each tool by name | Will be deprecated |
| Any other value | Same as search mode | Same as search mode | Same as search mode | — |

*Example:* full mode in Claude Code and in a JSON configuration.

> [tab] Claude Code
>
> ```bash theme={null}
> claude mcp add --transport http atlan "https://api.atlan.com/mcp?tools=full"
> ```
>
> Quote the URL so your shell keeps the `?`. If you already added `atlan`,
> run `claude mcp remove atlan` first.

> [tab] JSON configuration
>
> ```json theme={null}
> {
>   "mcpServers": {
>     "atlan": { "type": "http", "url": "https://api.atlan.com/mcp?tools=full" }
>   }
> }
> ```

> [!WARNING]
>
> Full mode will be deprecated later. Plan to move your clients to search mode.

### Changes from full mode

Search mode is the default on the plain URL, so a client that connected before now sees five tools instead of every tool.

| Area | Full mode | Search mode | What to update |
| - | - | - | - |
| Approvals, permission rules, and hooks | Match each tool's name | Match the runner; a rule for a tool's own name no longer matches | Replace them with [runner approvals](#tool-approvals), or keep `?tools=full` until you do |
| Session | `mcp__initialise` returns the `session_id` | The first search or call opens the session. A `session_id` you pass must be one you opened. | Nothing, if the agent follows the tool descriptions |
| Direct calls by tool name | Listed in `tools/list` | Still work, though `tools/list` does not show them. Without a `session_id`, the first call opens a session from its `rationale`. | Nothing |
| `mcp__initialise` | Opens the session | Still opens a session, for a client that already calls it. Its earlier name, `registry__initialise`, does too, but is not listed. | Nothing |
| Client's tool list | Every tool | Five tools | Reconnect the client, for example with `/mcp` in Claude Code |

## Sign-in methods

| Method | How the client sends it | Acts as | Best for |
| - | - | - | - |
| OAuth sign-in | The client follows the gateway's `401` to `https://api.atlan.com/.well-known/oauth-protected-resource/mcp` ([RFC 9728](https://www.rfc-editor.org/rfc/rfc9728)) and opens a browser. No token goes in the configuration. | You | People using an IDE or desktop client |
| Bearer token | `Authorization: Bearer <token>` on each request. See [Authentication](https://platform.atlan.com/api/how-tos/authentication.md) for supported credential paths. | The token's identity | CI jobs, services, and headless agents |

Clients that support MCP OAuth 2.1 need no extra configuration for OAuth sign-in. Load a bearer token from a secret store, never from a committed file.

> [!WARNING]
>
> An Atlan API key sent as a bearer token acts as the key, not as you: it reaches what the organization shares at its top level and the workspaces the key is added to.

## Tool approvals

In search mode your client approves the runner a call goes through, not the tool it runs. Each approval covers the runner's [tier](https://platform.atlan.com/gateway/mcp/concepts/search-mode.md#runners).

| Tool | **Always allow** covers | Name in Claude Code, for a server named `atlan` | Recommended |
| - | - | - | - |
| `mcp__search_tools` | Finding tools. Read only. | `mcp__atlan__mcp__search_tools` | Allow |
| `mcp__describe_tools` | Reading tool schemas. Read only. | `mcp__atlan__mcp__describe_tools` | Allow |
| `mcp__call_read_tool` | Tools that only read | `mcp__atlan__mcp__call_read_tool` | Allow |
| `mcp__call_write_tool` | Tools that write but are declared not destructive, and reads | `mcp__atlan__mcp__call_write_tool` | Allow |
| `mcp__call_tool` | Every tool you can reach through the gateway | `mcp__atlan__mcp__call_tool` | Leave to ask |

> [!WARNING]
>
> A tool's tier comes from its own labels. A tool labelled read-only that writes runs through `mcp__call_read_tool`, so allowing that runner allows it too.

*Example:* allow reads and non-destructive writes, and keep being asked before anything destructive.

> [tab] Claude Code
>
> In `.claude/settings.json`:
>
> ```json theme={null}
> {
>   "permissions": {
>     "allow": [
>       "mcp__atlan__mcp__search_tools",
>       "mcp__atlan__mcp__describe_tools",
>       "mcp__atlan__mcp__call_read_tool",
>       "mcp__atlan__mcp__call_write_tool"
>     ]
>   }
> }
> ```

> [tab] Claude Code in CI
>
> A script or CI job must allow each search mode tool it uses by its full
> name, or the search or the call is denied:
>
> ```bash theme={null}
> claude -p "<task>" --allowedTools "mcp__atlan__mcp__search_tools,mcp__atlan__mcp__describe_tools,mcp__atlan__mcp__call_read_tool,mcp__atlan__mcp__call_write_tool"
> ```

> [tab] Codex
>
> Codex asks before every call through `mcp__call_write_tool` or
> `mcp__call_tool`, including a read run through `mcp__call_tool`, and
> refuses such a call in `codex exec`. See
> [Connect Codex](https://platform.atlan.com/clients/openai/how-tos/codex.md#decide-how-codex-approves-tool-calls).

> [tab] Other clients
>
> Allow the same four tools under the names your client gives them, and
> leave `mcp__call_tool` to ask. If your client keeps a per-agent allowlist,
> check `arguments.name` before letting a call through.

## See also

* [Connect client to MCP Gateway](https://platform.atlan.com/gateway/mcp/how-tos/connect-a-client.md): Add the gateway to a client and make a first call.
* [How search mode works](https://platform.atlan.com/gateway/mcp/concepts/search-mode.md): Runners, tiers, and sessions.
* [MCP permissions](https://platform.atlan.com/gateway/mcp/concepts/permissions.md): The gateway's check after your client approves a call.
* [Search mode tools](https://platform.atlan.com/tools/mcp/references/search-mode-tools.md): Arguments and results for the five tools.


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