Initial commit: OpenClaw Skill Collection

6 custom skills (assign-task, dispatch-webhook, daily-briefing,
task-capture, qmd-brain, tts-voice) with technical documentation.
Compatible with Claude Code, OpenClaw, Codex CLI, and OpenCode.

openclaw-knowhow-skill/docs/reference/concepts/session-pruning.md

@@ -0,0 +1,121 @@
+> ## Documentation Index
+> Fetch the complete documentation index at: https://docs.openclaw.ai/llms.txt
+> Use this file to discover all available pages before exploring further.
+
+# null
+
+# Session Pruning
+
+Session pruning trims **old tool results** from the in-memory context right before each LLM call. It does **not** rewrite the on-disk session history (`*.jsonl`).
+
+## When it runs
+
+* When `mode: "cache-ttl"` is enabled and the last Anthropic call for the session is older than `ttl`.
+* Only affects the messages sent to the model for that request.
+* Only active for Anthropic API calls (and OpenRouter Anthropic models).
+* For best results, match `ttl` to your model `cacheControlTtl`.
+* After a prune, the TTL window resets so subsequent requests keep cache until `ttl` expires again.
+
+## Smart defaults (Anthropic)
+
+* **OAuth or setup-token** profiles: enable `cache-ttl` pruning and set heartbeat to `1h`.
+* **API key** profiles: enable `cache-ttl` pruning, set heartbeat to `30m`, and default `cacheControlTtl` to `1h` on Anthropic models.
+* If you set any of these values explicitly, OpenClaw does **not** override them.
+
+## What this improves (cost + cache behavior)
+
+* **Why prune:** Anthropic prompt caching only applies within the TTL. If a session goes idle past the TTL, the next request re-caches the full prompt unless you trim it first.
+* **What gets cheaper:** pruning reduces the **cacheWrite** size for that first request after the TTL expires.
+* **Why the TTL reset matters:** once pruning runs, the cache window resets, so follow‑up requests can reuse the freshly cached prompt instead of re-caching the full history again.
+* **What it does not do:** pruning doesn’t add tokens or “double” costs; it only changes what gets cached on that first post‑TTL request.
+
+## What can be pruned
+
+* Only `toolResult` messages.
+* User + assistant messages are **never** modified.
+* The last `keepLastAssistants` assistant messages are protected; tool results after that cutoff are not pruned.
+* If there aren’t enough assistant messages to establish the cutoff, pruning is skipped.
+* Tool results containing **image blocks** are skipped (never trimmed/cleared).
+
+## Context window estimation
+
+Pruning uses an estimated context window (chars ≈ tokens × 4). The base window is resolved in this order:
+
+1. `models.providers.*.models[].contextWindow` override.
+2. Model definition `contextWindow` (from the model registry).
+3. Default `200000` tokens.
+
+If `agents.defaults.contextTokens` is set, it is treated as a cap (min) on the resolved window.
+
+## Mode
+
+### cache-ttl
+
+* Pruning only runs if the last Anthropic call is older than `ttl` (default `5m`).
+* When it runs: same soft-trim + hard-clear behavior as before.
+
+## Soft vs hard pruning
+
+* **Soft-trim**: only for oversized tool results.
+  * Keeps head + tail, inserts `...`, and appends a note with the original size.
+  * Skips results with image blocks.
+* **Hard-clear**: replaces the entire tool result with `hardClear.placeholder`.
+
+## Tool selection
+
+* `tools.allow` / `tools.deny` support `*` wildcards.
+* Deny wins.
+* Matching is case-insensitive.
+* Empty allow list => all tools allowed.
+
+## Interaction with other limits
+
+* Built-in tools already truncate their own output; session pruning is an extra layer that prevents long-running chats from accumulating too much tool output in the model context.
+* Compaction is separate: compaction summarizes and persists, pruning is transient per request. See [/concepts/compaction](/concepts/compaction).
+
+## Defaults (when enabled)
+
+* `ttl`: `"5m"`
+* `keepLastAssistants`: `3`
+* `softTrimRatio`: `0.3`
+* `hardClearRatio`: `0.5`
+* `minPrunableToolChars`: `50000`
+* `softTrim`: `{ maxChars: 4000, headChars: 1500, tailChars: 1500 }`
+* `hardClear`: `{ enabled: true, placeholder: "[Old tool result content cleared]" }`
+
+## Examples
+
+Default (off):
+
+```json5  theme={null}
+{
+  agent: {
+    contextPruning: { mode: "off" },
+  },
+}
+```
+
+Enable TTL-aware pruning:
+
+```json5  theme={null}
+{
+  agent: {
+    contextPruning: { mode: "cache-ttl", ttl: "5m" },
+  },
+}
+```
+
+Restrict pruning to specific tools:
+
+```json5  theme={null}
+{
+  agent: {
+    contextPruning: {
+      mode: "cache-ttl",
+      tools: { allow: ["exec", "read"], deny: ["*image*"] },
+    },
+  },
+}
+```
+
+See config reference: [Gateway Configuration](/gateway/configuration)