# provider-anthropic

> Anthropic Messages API provider worker; implements provider::anthropic::stream and provider::anthropic::refresh_models behind llm-router.

| field | value |
|-------|-------|
| version | 1.1.6 |
| type | binary |
| repo | https://github.com/iii-hq/workers |
| supported_targets | x86_64-apple-darwin, aarch64-apple-darwin, i686-pc-windows-msvc, x86_64-pc-windows-msvc, aarch64-pc-windows-msvc, x86_64-unknown-linux-gnu, aarch64-unknown-linux-gnu, x86_64-unknown-linux-musl, armv7-unknown-linux-gnueabihf |
| author | iii |

## installation

```sh
iii worker add provider-anthropic@1.1.6
```

## dependencies

- `state` @ `^0.21.2`
- `llm-router` @ `^1.0.0`

## readme

# provider-anthropic

Claude models behind [llm-router](https://github.com/iii-hq/workers/tree/main/llm-router). Install this worker next
to the router, give it an API key, and the Anthropic catalog — streaming,
extended thinking, tool use, vision, automatic prompt caching — appears
behind the router's single front door (`router::chat` / `router::complete`).
You never call this worker directly: the router invokes it worker-to-worker,
and `iii-permissions.yaml` blocks agent access to `provider::anthropic::*`.

## Install

```bash
iii worker add provider-anthropic
```

The provider does nothing on its own — it plugs into the router:

```bash
iii worker add llm-router
```

`iii worker add` fetches the binary, writes a config block into
`~/.iii/config.yaml`, and the engine starts the worker on the next
`iii start`.

## Quickstart

Give the router a credential: paste a key into the `anthropic` slice of the
engine's `llm-router` configuration entry, or set `ANTHROPIC_API_KEY` in the
router's environment.

```json
{ "providers": { "anthropic": { "api_key": "sk-ant-…" } } }
```

The router picks up the change and kicks model discovery; Claude models land
in the catalog (`router::models::list`). Then make a first call — Node shown,
any SDK works:

```ts
const res = await iii.trigger('router::complete', {
  model: 'claude-sonnet-4-6',
  messages: [{ role: 'user', content: [{ type: 'text', text: 'Hello' }], timestamp: Date.now() }],
}, { timeout_ms: 320_000 }); // outer timeout ≥ the router's 300s stream budget
// res: { message, usage, provider, model } — message is the final AssistantMessage
```

For token-by-token streaming, call `router::chat` with an iii channel — the
walkthrough lives in [llm-router's Quickstart](https://github.com/iii-hq/workers/blob/main/llm-router/README.md).
Request extended thinking with `thinking_level`; the worker maps the level
to an Anthropic thinking budget from the model's catalog record. `xhigh`
degrades to `high` on models that don't support it, and the level is
dropped on models that don't support thinking at all.

## Configuration

All operator configuration lives in the router's `llm-router` entry — this
worker keeps no config of its own:

```jsonc
"anthropic": {
  "api_key": "sk-ant-…",                               // or ANTHROPIC_API_KEY in the router's env
  "api_url": "https://api.anthropic.com/v1/messages",  // override for proxies / gateways
  "max_tokens": 8192                                   // output ceiling when a request sets none
}
```

Worker-side environment variables:

| Variable | Default | Meaning |
|---|---|---|
| `PROVIDER_ANTHROPIC_CACHE` | enabled | `0`/`false` disables automatic prompt-cache markers |
| `III_WS_URL` | `ws://127.0.0.1:49134` | engine WebSocket to attach to when `--url` is not set |

The binary also takes the standard worker CLI flags: `--url` (engine
WebSocket), `--manifest` (print the registry manifest and exit), and
`--config` (accepted but ignored with a warning — provider config comes
from the `llm-router` configuration entry).

Prompt caching needs no setup: markers go on the system prompt, the tools
tail, and the last stable assistant turn whenever the prefix is big enough
to be worth a cache write.

## Models

The catalog slice is live `GET /v1/models` merged with a curated capability
snapshot — context windows, output ceilings, thinking budgets, pricing
(USD per MTok). Live ids the snapshot doesn't know get conservative
defaults; curated aliases the API doesn't enumerate are kept, so the catalog
has no cold hole before first discovery. The snapshot lives in
[`src/curated.rs`](src/curated.rs) — update it against models.dev when
Anthropic ships new models; discovery only supplies bare ids.

## Notes

- **Structured output:** the Messages API has no native JSON mode; every
  catalog record declares `supports_structured_output: false`, and a
  forwarded `response_format` is reported in `warnings` and ignored.
- **Errors:** 401/403 → `auth_expired`, 429 → `rate_limited`, 413/context →
  `context_overflow`, 5xx/network → `transient`, other 4xx → `permanent`.
  The worker never retries — the router owns retry policy.
- **Credentials:** resolved per request via `router::provider::resolve`
  (config slice → `ANTHROPIC_API_KEY` on the router → none). Both `api_key`
  (x-api-key) and `oauth` (Bearer) shapes work; v1 performs no OAuth refresh.
- **Identity binding:** the router issues a `registration_token` on first
  registration, persisted in iii-state (scope `provider-anthropic`). If that
  state is lost the router rejects re-registration — clear the binding on
  the router side to re-pair.

## Tests

```bash
cargo test                                            # unit (pure modules + TCP stubs)
III_ENGINE_BIN=$(which iii) cargo test --test integration -- --test-threads=1
```

The integration suite spawns a real engine, the real router (path dep), this
provider, and a local stub upstream — no external API calls anywhere.

## api reference

```json
{
  "functions": [
    {
      "description": "Cancel the in-flight upstream stream for a request_id (router::abort fan-out), stopping billed generation immediately.",
      "metadata": {
        "internal": true
      },
      "name": "provider::anthropic::abort",
      "request_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Input of a provider's `provider::<id>::abort`: actively cancel the in-flight upstream stream for `request_id` (the router's `request_id`, delivered to the provider as `resolution_key`) so billed generation stops immediately instead of waiting for the provider to notice the closed channel on its next write.",
        "properties": {
          "request_id": {
            "type": "string"
          }
        },
        "required": [
          "request_id"
        ],
        "title": "ProviderAbortRequest",
        "type": "object"
      },
      "response_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Output of `provider::<id>::abort`. `aborted: false` means the request was unknown — already finished, never started, or aborted before (idempotent).",
        "properties": {
          "aborted": {
            "type": "boolean"
          }
        },
        "required": [
          "aborted"
        ],
        "title": "ProviderAbortResponse",
        "type": "object"
      }
    },
    {
      "description": "Internal: router::ready subscriber that re-declares this provider and refreshes its catalog.",
      "metadata": {
        "internal": true
      },
      "name": "provider::anthropic::on_router_ready",
      "request_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Event delivered to a provider's `provider::<id>::on_router_ready` (the `router::ready` trigger payload, currently `{}`). Unknown fields are ignored.",
        "title": "RouterReadyEvent",
        "type": "object"
      },
      "response_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Ack returned by a provider's `provider::<id>::on_router_ready`.",
        "properties": {
          "ok": {
            "type": "boolean"
          }
        },
        "required": [
          "ok"
        ],
        "title": "ProviderReadyAck",
        "type": "object"
      }
    },
    {
      "description": "Refresh the Anthropic catalog slice from the upstream models endpoint and reconcile it through the router; returns the model count written.",
      "metadata": {
        "internal": true
      },
      "name": "provider::anthropic::refresh_models",
      "request_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Input of a provider's `provider::<id>::refresh_models` — takes no arguments. A struct (not `Value`) keeps the request schema concrete; unknown fields (e.g. the engine-injected `_caller_worker_id`) are ignored.",
        "title": "RefreshModelsRequest",
        "type": "object"
      },
      "response_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Output of `provider::<id>::refresh_models`.",
        "properties": {
          "count": {
            "format": "uint",
            "minimum": 0,
            "type": "integer"
          },
          "ok": {
            "type": "boolean"
          }
        },
        "required": [
          "count",
          "ok"
        ],
        "title": "RefreshModelsResponse",
        "type": "object"
      }
    },
    {
      "description": "Stream an Anthropic chat completion: resolve credentials, call the upstream Messages API, and relay AssistantMessageEvent frames to writer_ref.",
      "metadata": {
        "internal": true
      },
      "name": "provider::anthropic::stream",
      "request_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "definitions": {
          "AgentFunction": {
            "description": "Function invocation schema — what a provider sees as a `tools` array entry (README § Function invocation schema; adapter boundary). These describe iii functions exposed to the model, not provider-native tools.",
            "properties": {
              "description": {
                "type": "string"
              },
              "execution_mode": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "label": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "name": {
                "type": "string"
              },
              "parameters": true
            },
            "required": [
              "description",
              "name",
              "parameters"
            ],
            "type": "object"
          },
          "AgentMessage": {
            "anyOf": [
              {
                "$ref": "#/definitions/AssistantMessage"
              },
              {
                "$ref": "#/definitions/FunctionResultMessage"
              },
              {
                "$ref": "#/definitions/CustomMessage"
              },
              {
                "$ref": "#/definitions/UserMessage"
              }
            ],
            "description": "The canonical transcript message union. Untagged: the single-variant role tags disambiguate deserialization."
          },
          "AssistantMessage": {
            "properties": {
              "content": {
                "items": {
                  "$ref": "#/definitions/ContentBlock"
                },
                "type": "array"
              },
              "error_kind": {
                "anyOf": [
                  {
                    "$ref": "#/definitions/ErrorKind"
                  },
                  {
                    "type": "null"
                  }
                ]
              },
              "error_message": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "model": {
                "type": "string"
              },
              "native_stop_reason": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "provider": {
                "type": "string"
              },
              "role": {
                "$ref": "#/definitions/AssistantRoleTag"
              },
              "stop_reason": {
                "$ref": "#/definitions/StopReason"
              },
              "timestamp": {
                "format": "int64",
                "type": "integer"
              },
              "usage": {
                "anyOf": [
                  {
                    "$ref": "#/definitions/Usage"
                  },
                  {
                    "type": "null"
                  }
                ]
              },
              "warnings": {
                "items": {
                  "type": "string"
                },
                "type": [
                  "array",
                  "null"
                ]
              }
            },
            "required": [
              "content",
              "model",
              "provider",
              "role",
              "stop_reason",
              "timestamp"
            ],
            "type": "object"
          },
          "AssistantRoleTag": {
            "enum": [
              "assistant"
            ],
            "type": "string"
          },
          "ChannelDirection": {
            "enum": [
              "read",
              "write"
            ],
            "type": "string"
          },
          "ContentBlock": {
            "description": "Content blocks — the atomic units of message content (README § Content blocks).",
            "oneOf": [
              {
                "properties": {
                  "text": {
                    "type": "string"
                  },
                  "type": {
                    "enum": [
                      "text"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "text",
                  "type"
                ],
                "type": "object"
              },
              {
                "properties": {
                  "data": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "type": {
                    "enum": [
                      "image"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "data",
                  "mime",
                  "type"
                ],
                "type": "object"
              },
              {
                "properties": {
                  "signature": {
                    "type": [
                      "string",
                      "null"
                    ]
                  },
                  "text": {
                    "type": "string"
                  },
                  "type": {
                    "enum": [
                      "thinking"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "text",
                  "type"
                ],
                "type": "object"
              },
              {
                "description": "Opaque redacted thinking payload — replayed verbatim on the Anthropic wire.",
                "properties": {
                  "data": {
                    "type": "string"
                  },
                  "type": {
                    "enum": [
                      "redacted_thinking"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "data",
                  "type"
                ],
                "type": "object"
              },
              {
                "properties": {
                  "arguments": true,
                  "function_id": {
                    "type": "string"
                  },
                  "id": {
                    "type": "string"
                  },
                  "type": {
                    "enum": [
                      "function_call"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "arguments",
                  "function_id",
                  "id",
                  "type"
                ],
                "type": "object"
              },
              {
                "properties": {
                  "content": {
                    "items": {
                      "$ref": "#/definitions/ContentBlock"
                    },
                    "type": "array"
                  },
                  "function_call_id": {
                    "type": "string"
                  },
                  "is_error": {
                    "type": [
                      "boolean",
                      "null"
                    ]
                  },
                  "type": {
                    "enum": [
                      "function_result"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "content",
                  "function_call_id",
                  "type"
                ],
                "type": "object"
              }
            ]
          },
          "CustomMessage": {
            "properties": {
              "content": {
                "items": {
                  "$ref": "#/definitions/ContentBlock"
                },
                "type": "array"
              },
              "custom_type": {
                "type": "string"
              },
              "details": true,
              "display": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "role": {
                "$ref": "#/definitions/CustomRoleTag"
              },
              "timestamp": {
                "format": "int64",
                "type": "integer"
              }
            },
            "required": [
              "content",
              "custom_type",
              "role",
              "timestamp"
            ],
            "type": "object"
          },
          "CustomRoleTag": {
            "enum": [
              "custom"
            ],
            "type": "string"
          },
          "ErrorKind": {
            "enum": [
              "auth_expired",
              "rate_limited",
              "context_overflow",
              "transient",
              "permanent"
            ],
            "type": "string"
          },
          "FunctionResultMessage": {
            "properties": {
              "content": {
                "items": {
                  "$ref": "#/definitions/ContentBlock"
                },
                "type": "array"
              },
              "details": true,
              "function_call_id": {
                "type": "string"
              },
              "function_id": {
                "type": "string"
              },
              "is_error": {
                "type": "boolean"
              },
              "role": {
                "$ref": "#/definitions/FunctionResultRoleTag"
              },
              "timestamp": {
                "format": "int64",
                "type": "integer"
              }
            },
            "required": [
              "content",
              "details",
              "function_call_id",
              "function_id",
              "is_error",
              "role",
              "timestamp"
            ],
            "type": "object"
          },
          "FunctionResultRoleTag": {
            "enum": [
              "function_result"
            ],
            "type": "string"
          },
          "Model": {
            "description": "The capability record (README § Model descriptor).",
            "properties": {
              "context_window": {
                "format": "uint64",
                "minimum": 0,
                "type": "integer"
              },
              "display_name": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "id": {
                "type": "string"
              },
              "input_limit": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              },
              "max_output_tokens": {
                "format": "uint64",
                "minimum": 0,
                "type": "integer"
              },
              "pricing": {
                "anyOf": [
                  {
                    "$ref": "#/definitions/Pricing"
                  },
                  {
                    "type": "null"
                  }
                ]
              },
              "provider": {
                "type": "string"
              },
              "reasoning_efforts": {
                "items": {
                  "$ref": "#/definitions/ReasoningEffort"
                },
                "type": [
                  "array",
                  "null"
                ]
              },
              "supports_cache": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "supports_structured_output": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "supports_thinking": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "supports_tools": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "supports_vision": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "supports_xhigh": {
                "type": [
                  "boolean",
                  "null"
                ]
              },
              "thinking_budgets": {
                "additionalProperties": {
                  "format": "uint64",
                  "minimum": 0,
                  "type": "integer"
                },
                "type": [
                  "object",
                  "null"
                ]
              }
            },
            "required": [
              "context_window",
              "id",
              "max_output_tokens",
              "provider"
            ],
            "type": "object"
          },
          "Pricing": {
            "properties": {
              "cache_read": {
                "format": "double",
                "type": [
                  "number",
                  "null"
                ]
              },
              "cache_write": {
                "format": "double",
                "type": [
                  "number",
                  "null"
                ]
              },
              "input": {
                "format": "double",
                "type": [
                  "number",
                  "null"
                ]
              },
              "output": {
                "format": "double",
                "type": [
                  "number",
                  "null"
                ]
              }
            },
            "type": "object"
          },
          "ReasoningEffort": {
            "description": "One provider-native reasoning effort advertised for a specific model.\n\nValues intentionally remain strings: provider catalogs can add efforts without requiring a router-wide enum release first.",
            "properties": {
              "description": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "effort": {
                "type": "string"
              }
            },
            "required": [
              "effort"
            ],
            "type": "object"
          },
          "ResponseFormat": {
            "properties": {
              "schema": true,
              "type": {
                "type": "string"
              }
            },
            "required": [
              "type"
            ],
            "type": "object"
          },
          "StopReason": {
            "enum": [
              "end",
              "length",
              "function_call",
              "aborted",
              "error"
            ],
            "type": "string"
          },
          "StreamChannelRef": {
            "properties": {
              "access_key": {
                "type": "string"
              },
              "channel_id": {
                "type": "string"
              },
              "direction": {
                "$ref": "#/definitions/ChannelDirection"
              }
            },
            "required": [
              "access_key",
              "channel_id",
              "direction"
            ],
            "type": "object"
          },
          "ThinkingLevel": {
            "description": "\"minimal\" requests the lowest reasoning effort and needs only `thinking` support; levels map to provider-native knobs via `Model::thinking_budgets`.",
            "enum": [
              "minimal",
              "low",
              "medium",
              "high",
              "xhigh"
            ],
            "type": "string"
          },
          "Usage": {
            "properties": {
              "cache_read": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              },
              "cache_write": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              },
              "cost_usd": {
                "format": "double",
                "type": [
                  "number",
                  "null"
                ]
              },
              "input": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              },
              "output": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              },
              "reasoning": {
                "format": "uint64",
                "minimum": 0,
                "type": [
                  "integer",
                  "null"
                ]
              }
            },
            "type": "object"
          },
          "UserMessage": {
            "properties": {
              "content": {
                "items": {
                  "$ref": "#/definitions/ContentBlock"
                },
                "type": "array"
              },
              "role": {
                "$ref": "#/definitions/UserRoleTag"
              },
              "timestamp": {
                "format": "int64",
                "type": "integer"
              }
            },
            "required": [
              "content",
              "role",
              "timestamp"
            ],
            "type": "object"
          },
          "UserRoleTag": {
            "description": "Single-variant role tags: exact-match on deserialize, correct wire string on serialize, and they let `AgentMessage` be an untagged union.",
            "enum": [
              "user"
            ],
            "type": "string"
          }
        },
        "description": "Input of a provider worker's `provider::<id>::stream` iii function — what the router forwards per attempt. (No `PartialEq`: `iii_sdk::StreamChannelRef` doesn't implement it.)",
        "properties": {
          "max_output_tokens": {
            "format": "uint64",
            "minimum": 0,
            "type": [
              "integer",
              "null"
            ]
          },
          "messages": {
            "items": {
              "$ref": "#/definitions/AgentMessage"
            },
            "type": "array"
          },
          "model": {
            "type": "string"
          },
          "model_meta": {
            "anyOf": [
              {
                "$ref": "#/definitions/Model"
              },
              {
                "type": "null"
              }
            ]
          },
          "provider_options": true,
          "resolution_key": {
            "type": [
              "string",
              "null"
            ]
          },
          "response_format": {
            "anyOf": [
              {
                "$ref": "#/definitions/ResponseFormat"
              },
              {
                "type": "null"
              }
            ]
          },
          "system_prompt": {
            "type": [
              "string",
              "null"
            ]
          },
          "thinking_level": {
            "anyOf": [
              {
                "$ref": "#/definitions/ThinkingLevel"
              },
              {
                "type": "null"
              }
            ]
          },
          "tools": {
            "items": {
              "$ref": "#/definitions/AgentFunction"
            },
            "type": [
              "array",
              "null"
            ]
          },
          "writer_ref": {
            "$ref": "#/definitions/StreamChannelRef"
          }
        },
        "required": [
          "messages",
          "model",
          "writer_ref"
        ],
        "title": "ProviderStreamInput",
        "type": "object"
      },
      "response_schema": {
        "$schema": "http://json-schema.org/draft-07/schema#",
        "description": "Output of a provider's `provider::<id>::stream` (spec § stream contract): the function streams frames to `writer_ref` and returns this ack.",
        "properties": {
          "ok": {
            "type": "boolean"
          }
        },
        "required": [
          "ok"
        ],
        "title": "ProviderStreamOutput",
        "type": "object"
      }
    }
  ],
  "triggers": []
}
```