Claude Code Web Search Router (ModelRouter example)
This plugin demonstrates ModelRouter on Claude Code built-in web_search requests (see temp/1.json in the repo root for a captured request/response).
What it detects
- Inbound protocol
claude/anthropic tools[]withtypeweb_search_20250305orweb_search_20260209- Optional Claude Code heuristics: system text like “web search tool use”, or user text
Perform a web search for the query: …
Routes (route config)
| Value | Behavior |
|---|---|
fallback (default) |
Plugin executor runs antigravity → codex → xai → tavily (built-ins via host.model.*, Tavily in-plugin). On 429/503/502, tries the next backend in the same request. Backends that fail often are deprioritized on later requests (in-memory penalty; no extra config). |
antigravity_google / codex_web_search / xai_web_search / tavily |
Same orchestration for that backend’s chain member(s): execution retry + penalty apply when multiple backends are eligible. |
default_provider |
default_provider + optional default_provider_model via built-in AuthManager (not orchestrated). |
Routing for fallback requires at least one runnable backend (providers in AvailableProviders where needed, resolvable antigravity model, or tavily_api_keys). |
xAI web search notes (aligned with upstream docs)
- Model: xAI documents
grok-4.3for server-sideweb_search. This example setsTargetModeltogrok-4.3whenxai_modelis empty (do not forwardclaude-sonnet-4-6to xAI). - Request shape: Responses API
input+tools[]with"type": "web_search". Optionalfilters.allowed_domains/filters.excluded_domains(max 5 each, mutually exclusive). - Claude mapping today:
internal/translator/codex/claudecopies Claudeallowed_domains→filters.allowed_domains. Claudeblocked_domainsis not mapped toexcluded_domainsyet. - Executor:
xai_executornormalizes tools (drops unsupportedexternal_web_accessif present) and posts to/responses. - Response: Citations / server tool metadata come back through OpenAI Responses SSE and are converted toward Claude
server_tool_use/web_search_tool_resultwhere the response translator supports it.
Configuration
Plugin config lives under plugins.configs.claude-web-search-router (key must match the plugin name). Load the shared library via plugins.path.
Recommended: fallback chain (default)
Tries antigravity → codex → xai → tavily; configure tavily_api_keys so the last step can succeed when built-in providers are missing or unavailable.
plugins:
path:
- /absolute/path/to/examples/plugin/bin/claude-web-search-router-go.dylib
configs:
claude-web-search-router:
enabled: true
priority: 20
route: fallback
antigravity_model: "" # empty: registry lookup, then first supports_web_search
codex_model: "gpt-5.4-mini"
xai_model: "grok-4.3"
tavily_api_keys:
- "tvly-xxxxxxxx"
# - "tvly-yyyyyyyy" # optional: round-robin
require_web_search_only: true
Omit route to use the same default (fallback).
Minimal fallback (Tavily as last resort only)
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: fallback
tavily_api_keys:
- "tvly-xxxxxxxx"
require_web_search_only: true
Single backend (no fallback)
Antigravity only:
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: antigravity_google
antigravity_model: "gemini-3.1-flash-lite"
require_web_search_only: true
Codex only:
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: codex_web_search
codex_model: "gpt-5.4-mini"
require_web_search_only: true
xAI only:
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: xai_web_search
xai_model: "grok-4.3"
require_web_search_only: true
Tavily only (plugin executor):
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: tavily
tavily_api_keys:
- "tvly-xxxxxxxx"
require_web_search_only: true
Built-in provider via default_provider:
plugins:
configs:
claude-web-search-router:
enabled: true
priority: 20
route: default_provider
default_provider: claude
default_provider_model: ""
require_web_search_only: true
Disable or relax detection
plugins:
configs:
claude-web-search-router:
enabled: false # plugin declines; host may use default Claude path
# Or keep enabled but allow mixed tool lists:
claude-web-search-router:
enabled: true
route: fallback
require_web_search_only: false
Config field reference
| Field | Description |
|---|---|
enabled |
false → Handled: false for all web_search matches |
priority |
Host plugin order for ModelRouter (higher runs earlier; see main repo plugins docs) |
route |
fallback (default), antigravity_google, codex_web_search, xai_web_search, tavily, default_provider |
antigravity_model |
Antigravity execution model; never the client Claude model name |
codex_model |
Codex model; empty → gpt-5.4-mini |
xai_model |
xAI model; empty → grok-4.3 |
default_provider / default_provider_model |
Used when route=default_provider |
tavily_api_keys |
Required for route=tavily or fallback last step |
require_web_search_only |
true matches Claude Code–style exclusive web_search tools |
Build
make -C examples/plugin bin/claude-web-search-router-go.dylib
Use .so on Linux and .dll on Windows. Point plugins.path at the built artifact.