Built-in Tools

Responses-passthrough models can run metered server-side tools in addition to ordinary model tokens.

Available tools

Tool type	Meter
web_search or web_search_preview	Each reported search call

{
  "model": "YOUR_LIVE_RESPONSES_MODEL",
  "input": "Find the latest official release note and summarize it.",
  "tools": [{"type": "web_search"}]
}

Tool charges are separate usage rows so they can be audited and refunded independently.

Other tool types

• Function and custom tools have no separate Primex tool meter. Their model work is covered by token usage.
• Remote MCP tools are covered by the model's reported token usage. See MCP.
• code_interpreter, image_generation, and file_search built-ins are not available yet. Primex returns tool_not_available instead of forwarding an unmetered cost. Code Interpreter is time-billed by Azure and Responses does not expose an authoritative billable-duration field.
• Chat-only models cannot represent Responses built-ins. Use a model marked for native Responses support in the live catalogue.

Claude Skills

GET /v1/skills with your Primex API key and anthropic-version: 2023-06-01 lists Anthropic's built-in Excel (xlsx), PowerPoint (pptx), PDF (pdf) and Word (docx) Skills. Optional source=anthropic is supported; customer-uploaded Skills are not exposed.

Skills execution uses the native Anthropic API and can produce downloadable files. The supported built-in Skills depend on the model:

Model ID	Supported Skills
claude-sonnet-4-6	Excel (xlsx), PowerPoint (pptx), PDF (pdf), Word (docx)
claude-haiku-4-5	Excel (xlsx)
claude-opus-4-8	Excel (xlsx)
claude-fable-5	Excel (xlsx)
claude-fable-5-1	Excel (xlsx)

Every Skill in a request must be supported by the selected model. Discovery lists all four built-ins; it does not mean every model supports every Skill. See Claude Files for uploads and generated-file downloads.

Minimal Excel creation/download has been verified on all five models. Minimal PDF, Word and PowerPoint workflows have been verified on Sonnet 4.6. ZIP-labeled .pptx output is accepted only after bounded PowerPoint package verification, then returned with the standard PowerPoint MIME type.

Use native, non-streaming /v1/messages requests with a fresh container, at most 1024 output tokens and a required X-Primex-Operation-ID. Include both tools below explicitly. The reviewed web-fetch version makes code execution free of a separate container-time fee; model input, output and cache tokens still cost money. Web fetch has no separate tool fee. Its returned content adds model tokens. Primex does not insert web fetch on your behalf.

{
  "model": "claude-sonnet-4-6",
  "max_tokens": 1024,
  "stream": false,
  "container": {"skills": [{"type": "anthropic", "skill_id": "xlsx", "version": "latest"}]},
  "tools": [
    {"type": "code_execution_20260120", "name": "code_execution"},
    {"type": "web_fetch_20260209", "name": "web_fetch", "max_uses": 1,
     "max_content_tokens": 2048, "allowed_domains": ["example.invalid"]}
  ],
  "messages": [{"role": "user", "content": "Create a small example spreadsheet. Do not fetch external pages."}]
}

For Excel, you can replace the example model with any model in the table.

Use anthropic-version: 2023-06-01 without beta headers. Web fetch allows at most 3 uses and 4096 content tokens; preserve your intended domain restrictions. Only one execution may be pending per account, with five completed fresh containers in a rolling 24 hours. Custom Skills, container reuse, streaming, standalone code execution, paid web search and programmatic client-tool calls remain unsupported. The free count-tokens endpoint cannot budget this execution envelope.

Responses use account-owned container_prx_… and generated file_prx_… IDs. Download an owned generated document/text file at GET /v1/files/{id}/content; outputs expire after 24 hours and share the Files count/byte limits. Downloads are free and work at zero wallet balance. Supplier deletion is retried separately after expiry; expiry alone does not confirm physical deletion.

On anthropic_execution_recovery_required, do not retry or continue automatically, including with a new operation ID. Contact support with X-Primex-Request-ID. An uncertain billing acknowledgement may already have committed the charge and made outputs visible in your Files list. The same operation ID cannot dispatch another execution, even if its payload changes.