A comparison of terminology used across major AI coding tools (as of February 2026).
| Concept | Claude Code | OpenAI Codex | Kiro IDE | Kiro CLI | Gemini CLI | OpenCode |
|---|---|---|---|---|---|---|
| The AI itself | Agent / Subagent | Agent | Agent + Autonomous Agent (async) | Agent | Agent (ReAct loop) | Agent |
| Specialized agents | Subagents (Explore, Plan, Bash, etc.) + Custom Agents | — | Subagents + Powers (context bundles) | Subagents + Custom Agents | Sub-agents (experimental: cli_help, routing, generalist) + Jules (async) + Custom Agents | Primary Agents (Build, Plan) + Subagents (General, Explore) + Custom Agents |
| Callable capabilities | Tools (Read, Edit, Bash, Grep, Glob, Write, WebFetch, WebSearch, etc.) | Tools (shell, file read/write, apply patch, etc.) | Tools (built-in + MCP tools) | Built-in Tools (read, write, shell, aws, grep, glob, subagent, web search/fetch) | Tools (ReadFile, WriteFile, Edit, Shell, FindFiles, SearchText, GoogleSearch, WebFetch, SaveMemory, etc.) | Tools (bash, read, write, edit, grep, glob, list, patch, lsp, webfetch, websearch, etc.) |
| External integrations | MCP Servers | MCP Servers | MCP Servers (local + remote) | MCP Servers (local + remote, with MCP Registry governance) | MCP Servers (stdio + SSE transports) | MCP Servers (local + remote with OAuth) |
| Reusable workflows | Skills (slash commands) + Plugins | Skills + /review + /plan slash commands | Specs (SDD) + Agent Skills | Skills (progressively loaded, on-demand) | Extensions + Agent Skills (SKILL.md) + Custom Slash Commands | Skills (SKILL.md files in .opencode/skills/) |
| Event-driven automation | Hooks (14 events: PreToolUse, PostToolUse, SessionStart/End, UserPromptSubmit, Stop, SubagentStart/Stop, PreCompact, etc.) | — | Agent Hooks (file save/create/delete, prompt submit, agent turn, pre/post tool use) | Hooks (agentSpawn, userPromptSubmit, preToolUse, postToolUse, stop) | Hooks (SessionStart/End, BeforeModel/AfterModel, BeforeTool/AfterTool, BeforeAgent/AfterAgent, BeforeToolSelection, PreCompress) | Plugins (tool.execute.before/after, file.edited, session events, etc.) |
| Project-level AI instructions | CLAUDE.md (hierarchical: user/project/local) | AGENTS.md (hierarchical, with configurable fallbacks) | Steering Files (.kiro/steering/) | Steering Files (.kiro/steering/) + Agent config JSON | GEMINI.md (hierarchical, multi-file, configurable filename) | AGENTS.md (also reads CLAUDE.md for compatibility) |
| Persistent memory | Auto memory (~/.claude/projects/<project>/memory/) + Subagent memory | Thread memory (experimental) | Autonomous Agent learns from PR feedback | Knowledge management (experimental, /knowledge) | save_memory (built-in tool) + Conductor (extension) | — (available via community plugins) |
| Bundled packages | Plugins (commands, agents, skills, hooks, MCP, LSP) | — | Powers (MCP + steering + hooks) + Agent Skills + Open VSX plugins | Custom Agents (bundled config + tools + steering) | Extensions (MCP + context + slash commands + skills) | Plugins (JS/TS modules with hooks + custom tools) |
| Background/async work | Background tasks | Automations (scheduled runs in background worktrees) | Autonomous Agent (runs for days, up to 10 concurrent tasks) | Subagent parallelism | Jules (async in VM, up to 15 concurrent tasks) + Sub-agents | — (available via community plugins) |
| Parallel execution | Subagent parallelism | Cloud worktrees | Subagents (parallel) + Autonomous Agent (10 concurrent) | Subagents (isolated context, live progress) | Jules (15 concurrent tasks) + Sub-agents (experimental) | General subagent (limited parallelism) |
| Planning mode | Plan agent | /plan slash command | Spec-Driven Development + Plan Agent | Plan agent (built-in, Shift+Tab or /plan) | Plan Mode (experimental, read-only) | Plan agent (read-only, Tab to switch) |
| Configuration | settings.json (JSON, hierarchical scopes) | config.toml (TOML, with profiles) | .kiro/ directory (steering md, hooks, agents md, skills) | Agent config JSON + Steering Markdown | settings.json (JSON) + GEMINI.md | opencode.json (JSON/JSONC) |