feat: add Anthropic fast mode support

docs/concepts/model-providers.md

@@ -62,6 +62,7 @@ OpenClaw ships with the pi‑ai catalog. These providers require **no**
 - Optional rotation: `ANTHROPIC_API_KEYS`, `ANTHROPIC_API_KEY_1`, `ANTHROPIC_API_KEY_2`, plus `OPENCLAW_LIVE_ANTHROPIC_KEY` (single override)
 - Example model: `anthropic/claude-opus-4-6`
 - CLI: `openclaw onboard --auth-choice token` (paste setup-token) or `openclaw models auth paste-token --provider anthropic`
+- Direct API-key models support the shared `/fast` toggle and `params.fastMode`; OpenClaw maps that to Anthropic `service_tier` (`auto` vs `standard_only`)
 - Policy note: setup-token support is technical compatibility; Anthropic has blocked some subscription usage outside Claude Code in the past. Verify current Anthropic terms and decide based on your risk tolerance.
 - Recommendation: Anthropic API key auth is the safer, recommended path over subscription setup-token auth.
 

docs/providers/anthropic.md

@@ -44,6 +44,34 @@ openclaw onboard --anthropic-api-key "$ANTHROPIC_API_KEY"
   - [Adaptive thinking](https://platform.claude.com/docs/en/build-with-claude/adaptive-thinking)
   - [Extended thinking](https://platform.claude.com/docs/en/build-with-claude/extended-thinking)
 
+## Fast mode (Anthropic API)
+
+OpenClaw's shared `/fast` toggle also supports direct Anthropic API-key traffic.
+
+- `/fast on` maps to `service_tier: "auto"`
+- `/fast off` maps to `service_tier: "standard_only"`
+- Config default:
+
+```json5
+{
+  agents: {
+    defaults: {
+      models: {
+        "anthropic/claude-sonnet-4-5": {
+          params: { fastMode: true },
+        },
+      },
+    },
+  },
+}
+```
+
+Important limits:
+
+- This is **API-key only**. Anthropic setup-token / OAuth auth does not honor OpenClaw fast-mode tier injection.
+- OpenClaw only injects Anthropic service tiers for direct `api.anthropic.com` requests. If you route `anthropic/*` through a proxy or gateway, `/fast` leaves `service_tier` untouched.
+- Anthropic reports the effective tier on the response under `usage.service_tier`. On accounts without Priority Tier capacity, `service_tier: "auto"` may still resolve to `standard`.
+
 ## Prompt caching (Anthropic API)
 
 OpenClaw supports Anthropic's prompt caching feature. This is **API-only**; subscription auth does not honor cache settings.

docs/tools/thinking.md

@@ -54,6 +54,8 @@ title: "Thinking Levels"
   4. Fallback: `off`
 - For `openai/*`, fast mode applies the OpenAI fast profile: `service_tier=priority` when supported, plus low reasoning effort and low text verbosity.
 - For `openai-codex/*`, fast mode applies the same low-latency profile on Codex Responses. OpenClaw keeps one shared `/fast` toggle across both auth paths.
+- For direct `anthropic/*` API-key requests, fast mode maps to Anthropic service tiers: `/fast on` sets `service_tier=auto`, `/fast off` sets `service_tier=standard_only`.
+- Anthropic fast mode is API-key only. OpenClaw skips Anthropic service-tier injection for Claude setup-token / OAuth auth and for non-Anthropic proxy base URLs.
 
 ## Verbose directives (/verbose or /v)