Kjell Tore Guttormsen
624f5edabc
The knowledge base was frozen at ~v2.1.111, describing an Opus-4.7 world after CC shipped Opus 4.8 and Fable 5. Refreshed three agent-facing knowledge files; every fact re-verified against the official changelog (~/.claude/cache/changelog.md, CC 2.1.181) on 2026-06-18. - feature-evolution.md: new Opus-4.8-era rows above the v2.1.111 freeze -- Opus 4.8 default + /effort xhigh (2.1.154), Fable 5 Mythos-class (2.1.170), post-session hook (2.1.169), MessageDisplay (2.1.152), /simplify -> /code-review (2.1.147), /config key=value (2.1.181). - hook-events-reference.md: 26 -> 28 events (+MessageDisplay, +post-session); documented Stop/SubagentStop additionalContext output field. - claude-code-capabilities.md: 2026-06 model/effort lineup table; bundled skills /simplify -> /code-review; documented /config key=value. - cc-2.1.x-changelog-delta.md: marked SUPERSEDED by the gap-matrix. Verification caught two version errors in STATE/matrix, corrected to the changelog: - Stop/SubagentStop additionalContext is 2.1.163, not 2.1.165 (2.1.165 was "Bug fixes" only; matrix row 109 already said 2.1.163). - settings `agent` field introduced 2.0.59; 2.1.157 = honored for dispatched `claude agents` sessions, not the introduction. New tests/knowledge/knowledge-staleness.test.mjs (8 tests) encodes the verified facts as a re-freeze guard (RED before edits, GREEN after). Full suite: 850/850 green (+8). self-audit PASS, A(100)/A(97).
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Claude Code Feature Evolution
Timeline of major features, most recent first. Covers features with configuration impact. Source: Official Claude Code documentation, verified 2026-04-03; 2026-04 entries verified via research/03-claude-code-changes-config-surfaces.md (2026-04-19). 2026-06 entries (window v2.1.114–v2.1.181) re-verified against the official Claude Code changelog on 2026-06-18.
2026
| Approx. Date | Feature | Config Impact |
|---|---|---|
| 2026-06 (v2.1.181) | /config key=value in-session settings |
Set any setting from the prompt — /config thinking=false — in interactive, -p, and Remote Control. Lets /config-audit settings recommendations be applied without hand-editing settings.json. |
| 2026-05 (v2.1.170) | Claude Fable 5 (Mythos-class) | New top-capability model family; 1M context by default (a [1m] id suffix is normalised away). Auto mode falls back to the best available Opus for orgs without Opus 4.8 enabled. |
| 2026-05 (v2.1.169) | post-session lifecycle hook |
Runs after the session ends and before the workspace is deleted — snapshot uncommitted work or export logs (self-hosted runner). Kebab-case, distinct from SessionEnd. |
| 2026-04 (v2.1.154) | Opus 4.8 — new default model | Defaults to high effort; /effort xhigh (effortLevel: "xhigh") is the new top tier for the hardest tasks. The lean system prompt is now the default for all models except Haiku, Sonnet, and Opus 4.7 and earlier. The settings agent field is honored for dispatched claude agents sessions (v2.1.157). |
| 2026-04 (v2.1.152) | MessageDisplay hook event |
Hooks can transform or hide assistant message text as it is displayed. |
| 2026-04 (v2.1.147) | /simplify renamed to /code-review |
Reports correctness bugs at a chosen effort (/code-review high); --comment posts inline PR comments. The old cleanup-and-fix behaviour was removed. |
| 2026-04 (v2.1.111) | Opus 4.7 + token-efficiency surfaces | New env vars ENABLE_PROMPT_CACHING_1H, FORCE_PROMPT_CACHING_5M, CLAUDE_CODE_DISABLE_1M_CONTEXT. New settings keys around tui / autoScrollEnabled. Granular commit attribution via attribution.commit / attribution.pr (replaces includeCoAuthoredBy). |
| 2026-04 (v2.1.83+) | Sandbox + managed-only enterprise lockdown | Added settings keys: sandbox.enabled, sandbox.failIfUnavailable, sandbox.allowUnsandboxedCommands, sandbox.filesystem.allowRead/denyRead, sandbox.network.deniedDomains/allowedDomains, sandbox.enableWeakerNetworkIsolation. Managed-only flags: allowManagedHooksOnly, allowManagedMcpServersOnly, allowManagedPermissionRulesOnly. |
| 2026-03 (v2.1.91) | disableSkillShellExecution |
Blocks inline !command shell expansion in skills. Mitigates skill-side prompt-injection vector. |
| 2026-03 (v2.1.92) | forceRemoteSettingsRefresh |
Fail-closed on managed-settings fetch failure (previously fail-open). |
| Q1 2026 | Agent Teams (experimental) | Enable via CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 or env in settings.json. Configure display mode via ~/.claude.json teammateMode. Hooks: TeammateIdle, TaskCreated, TaskCompleted. |
| Q1 2026 | Elicitation events | Elicitation and ElicitationResult hook events added. MCP servers can request user input; hooks control and log these requests. |
| Q1 2026 | SubagentStart / SubagentStop hooks |
Added hook events for subagent lifecycle. SubagentStop is blocking — exit code 2 acts as a quality gate. |
| Q1 2026 | ConfigChange hook event |
Fires when any config file changes on disk. Matcher: user_settings, project_settings, local_settings, policy_settings, skills. |
| Q1 2026 | InstructionsLoaded hook event |
Fires when CLAUDE.md/.claude/rules files load. Useful for debugging instruction loading order and content. |
| Q1 2026 | StopFailure / PostToolUseFailure hooks |
Error-path hooks added for better error observability and retry logic. |
| Q1 2026 | WorktreeCreate / WorktreeRemove hooks |
WorktreeCreate is blocking; hook can return custom worktree path to replace Claude's default git worktree logic. Enables non-git VCS support. |
| Q1 2026 | PermissionDenied hook |
Info-only event when auto mode denies a tool. Useful for logging and auditing denied operations. |
| Q1 2026 | SessionEnd hook |
Fires on session termination. Matcher: clear, resume, logout, prompt_input_exit, other. |
| Q1 2026 | HTTP hook type | type: "http" hook handler posts to HTTP endpoints. allowedHttpHookUrls and httpHookAllowedEnvVars settings for security controls. |
| Q1 2026 | Agent-type hooks | type: "agent" hook handler — full subagent with tools for complex validation. |
2025
| Approx. Date | Feature | Config Impact |
|---|---|---|
| Late 2025 | Plugins system | Namespaced skill/agent/hook/MCP bundles. enabledPlugins in settings.json. Plugin marketplace support. --plugin-dir for development. /reload-plugins command. bin/ for CLI tools. |
| Late 2025 | LSP plugins | .lsp.json at plugin root provides real-time code intelligence. Official LSP plugins for TypeScript, Python, Rust, etc. |
| Late 2025 | Output styles | outputStyle setting; ~/.claude/output-styles/*.md and .claude/output-styles/*.md. System prompt modification (stronger than CLAUDE.md). Built-in: Default, Explanatory, Learning. |
| Late 2025 | Status line | statusLine key in settings.json. Script receives stdin JSON with cost, context window %, model, worktree, session info. /statusline command for natural language config. |
| Late 2025 | Skills system (v2) | Major expansion of frontmatter fields: context: fork, disable-model-invocation, user-invocable, paths, hooks, shell. !command`` dynamic context. $ARGUMENTS[N] indexing. |
| Late 2025 | Subagent isolation: worktree | isolation: worktree in agent frontmatter. Each invocation gets own git worktree. Auto-cleaned on completion. |
| Late 2025 | Subagent persistent memory | memory: "user" in agent frontmatter. Accumulates knowledge to ~/.claude/agent-memory/. |
| Late 2025 | Subagent preloaded skills | skills: array in agent frontmatter. Full skill content injected at agent startup (vs. description-only in regular sessions). |
| Mid 2025 | Worktrees | claude --worktree <name> CLI flag. .worktreeinclude for gitignored file propagation. worktree.symlinkDirectories and worktree.sparsePaths settings. |
| Mid 2025 | MCP integration | .mcp.json project-level config. ~/.claude.json mcpServers. Three server types: stdio, http, sse. Resources via @server:path. Prompts as slash commands. |
| Mid 2025 | Auto-memory | ~/.claude/projects/<project>/memory/MEMORY.md. autoMemoryEnabled setting. autoMemoryDirectory for custom path. Topic files loaded on demand. |
| Mid 2025 | Managed settings | managed-settings.json, managed-settings.d/*.json. Org-wide config at highest precedence. Managed-only keys for enterprise lockdown. |
| Mid 2025 | PreCompact/PostCompact hooks |
Hooks for context compaction lifecycle. Matcher: manual, auto. |
| Early 2025 | Hooks system (v1) | Initial hooks in settings.json. Events: SessionStart, UserPromptSubmit, PreToolUse, PermissionRequest, PostToolUse, Stop, Notification, CwdChanged, FileChanged, PreCompact, PostCompact. command and prompt handler types. |
| Early 2025 | .claude/rules/ directory |
Path-specific rules with paths: frontmatter. Lazy loading — only loads when Claude works on matching files. |
| Early 2025 | Keybindings | ~/.claude/keybindings.json. JSON Schema available. Chord support. Vim mode. 20+ contexts and 40+ bindable actions. |
| Early 2025 | CLAUDE.local.md |
Project-local personal companion file. Gitignored. Appended after CLAUDE.md. |
| Early 2025 | Extended thinking | alwaysThinkingEnabled setting. effortLevel (low/medium/high/max). MAX_THINKING_TOKENS env var. |
| Early 2025 | Auto mode | autoMode object in settings.json (user/local only). environment, allow, soft_deny arrays. disableAutoMode setting. |
2024
| Approx. Date | Feature | Config Impact |
|---|---|---|
| Late 2024 | Subagents (v1) | .claude/agents/<name>.md. ~/.claude/agents/. Frontmatter: model, tools, disallowedTools, permissionMode, color, maxTurns. |
| Late 2024 | Skills system (v1) | ~/.claude/skills/<name>/SKILL.md. .claude/skills/<name>/SKILL.md. Legacy .claude/commands/<name>.md also supported. Basic frontmatter. |
| Mid 2024 | @import in CLAUDE.md |
@path/to/file syntax for modular CLAUDE.md. Max 5 hops. HTML comment stripping. |
| Mid 2024 | settings.json | .claude/settings.json (project), ~/.claude/settings.json (user), .claude/settings.local.json (local). Permissions, env, hooks. |
| Early 2024 | CLAUDE.md | Initial project-level instructions. User-level ~/.claude/CLAUDE.md. Lazy loading of subdirectory files. Directory walk. |