Merge remote-tracking branch 'origin/master' into codex/trim-ai-prose

# Conflicts:
#	docs/AGENTS.md
#	docs/config-catalog.md
#	packages/bash/bash-sandbox/src/index.ts
#	packages/bash/bash/src/session-mode.ts
#	packages/bash/tool-bash/README.md
#	packages/code-runtime/code-runtime-worker/README.md
#	packages/compact/compact/src/index.ts
#	packages/core/agent-core/README.md
#	packages/hooks/hooks-claude/src/config.ts
#	packages/hooks/hooks-claude/src/index.ts
#	packages/hooks/hooks-codex/src/config.ts
#	packages/hooks/hooks-codex/src/index.ts
#	packages/llm/llm/README.md
#	packages/session-persistence/session-persistence-jsonl/README.md
#	packages/session-persistence/session-persistence/README.md
#	packages/skill/skill-local/README.md
#	packages/support/acp-snapshot/README.md
#	packages/support/invariants/src/index.ts
#	packages/ui/acp/README.md
#	packages/ui/jsonrpc-agent/README.md
#	packages/ui/jsonrpc/README.md
#	packages/ui/permission/README.md
#	packages/ui/user-approval/README.md
#	packages/ui/user-interaction/README.md
#	packages/web/web-search-deepseek/README.md

packages/skill/tool-skill/README.md

@@ -23,3 +23,92 @@ Resource guidance resolves only paths or URLs explicitly referenced by the instr
 An unresolved name reports that the skill is unknown or no longer available. Invalid names and `disableModelInvocation: true` skills produce distinct error results.
 
 The tool does not call `agent.inject()` in v1. Its result is already recorded as the tool result and becomes available to the next model step without duplicating the content as synthetic context.
+
+## Model Experience
+
+### Session prefix
+
+**What the model sees**: If model-invocable skills exist and this exact `skill` tool is visible, the agent receives the catalog template below, with one data-dependent entry per sorted skill. The catalog is a frozen user-role session prefix.
+
+**Token effect**: Repeated input cost scales with skill count and `catalogDescriptionMaxLength`; no catalog tokens are sent when the list is empty or the tool is hidden or shadowed.
+
+#### Skill catalog template
+
+```markdown
+<system-reminder>
+A skill is a reusable set of task-specific instructions. The following skills are available in this session:
+
+<available_skills>
+- `<name>`: <normalized-and-capped-description>
+</available_skills>
+
+If the user names a skill, or the task clearly matches a skill's description, call the `skill` tool with the exact skill name before taking task actions. Load all applicable skills, then follow their full instructions. This catalog contains summaries only; do not infer or follow a skill's instructions until it has been loaded.
+</system-reminder>
+```
+
+### Tool schema
+
+**What the model sees**: The model sees the generated [`skill` schema](../../../docs/tool-catalog.md#deepseek-aidsh-tool-skill).
+
+**Token effect**: Fixed schema cost per request where the tool is visible.
+
+### Tool result
+
+**What the model sees**: A successful call uses the result template and the provider-managed, directory, URL, or opaque resource guidance below.
+
+**Token effect**: Loaded instructions are data-dependent tool-result tokens, resent on later steps until compaction; no duplicate `agent.inject()` copy is made.
+
+#### Skill result template
+
+```markdown
+<skill_content name="<escaped-name>">
+<skill_resources>
+<resource-guidance>
+</skill_resources>
+
+<skill_instructions>
+<provider-owned-instruction-body>
+</skill_instructions>
+</skill_content>
+```
+
+#### Provider-managed resource guidance
+
+```markdown
+Resources for this skill are managed by provider "<provider>".
+Load referenced resources only as needed.
+```
+
+#### Directory resource guidance
+
+```markdown
+Base directory for this skill: <path>
+Resolve relative paths mentioned by this skill against the base directory before using them. Load referenced resources only as needed.
+```
+
+#### URL resource guidance
+
+```markdown
+Base URL for this skill: <url>
+Resolve relative URLs mentioned by this skill against the base URL before using them. Load referenced resources only as needed.
+```
+
+#### Opaque resource guidance
+
+```markdown
+Resources for this skill: <description>
+Load referenced resources only as needed.
+```
+
+### Tool errors
+
+**What the model sees**: Invalid or stale selections return exactly `Error: invalid skill name "<name>"`, `Error: skill "<name>" is unknown or no longer available`, or `Error: skill "<name>" is not available for model invocation`. Provider-thrown lookup text is data-dependent and receives the same `Error: <message>` wrapper.
+
+**Token effect**: Only a failing call adds these retained tokens.
+
+## Known Limitations and Deferred Work
+
+- **The catalog omits `whenToUse`, source, and provider metadata** — routing is based only on name and a capped description; `whenToUse` remains provider metadata and is not rendered by the loaded wrapper either.
+- **Loaded instruction bodies have no size cap** — a provider can return a skill large enough to consume substantial next-step context; only catalog descriptions are truncated.
+- **Resources are guidance, not attachments** — the tool reports a base directory/URL/opaque hint but neither enumerates nor fetches referenced files for the model.
+- **Loading is one-shot text** — there is no partial, streaming, or cached-content handle when a remote provider is slow or a skill body is large.