# Capability Seams And Core Services A service can be a core spine service, a swappable capability seam, or a bundle/composition point. The graph shows the package that owns the service declaration, known implementation packages, and packages that consume the service directly. ```mermaid flowchart LR pkg_llm["llm"] svc_llm["ctx.llm
LLM adapter registry"] pkg_llm_deepseek["llm-deepseek"] pkg_llm_pi_ai["llm-pi-ai"] pkg_llm_replay["llm-replay"] pkg_agent_loop["agent-loop"] pkg_compact_basic["compact-basic"] pkg_session["session"] svc_sessions["ctx.sessions
In-memory session store"] pkg_agent["agent"] pkg_session_persistence["session-persistence"] pkg_session_query["session-query"] pkg_subagent_inprocess["subagent-inprocess"] pkg_invariants["invariants"] svc_sessionPersistence["ctx.sessionPersistence
Durable session persistence seam"] pkg_session_persistence_jsonl["session-persistence-jsonl"] pkg_session_persistence_sqlite["session-persistence-sqlite"] pkg_acp["acp"] svc_sessionQuery["ctx.sessionQuery
Exact session-history reads"] pkg_system_prompt["system-prompt"] svc_systemPrompt["ctx.systemPrompt
System prompt assembly registry"] pkg_tools["tools"] pkg_tool_fs["tool-fs"] pkg_tool_web["tool-web"] svc_tools["ctx.tools
Tool registry and guarded execution pipeline"] pkg_tool_ask_user["tool-ask-user"] pkg_tool_bash["tool-bash"] pkg_tool_cordis["tool-cordis"] pkg_tool_skill["tool-skill"] pkg_tool_subagent["tool-subagent"] pkg_tool_todo["tool-todo"] pkg_user_interaction["user-interaction"] svc_userInteraction["ctx.userInteraction
Human question/answer seam"] pkg_stdio_agent["stdio-agent"] pkg_skill["skill"] svc_skills["ctx.skills
Skill provider registry"] pkg_skill_local["skill-local"] svc_agents["ctx.agents
Agent registry"] svc_agentLoop["ctx.agentLoop
Concrete loop driver"] pkg_agent_core["agent-core"] pkg_bash["bash"] svc_bash["ctx.bash
Bash executor seam"] pkg_bash_local["bash-local"] pkg_bash_sandbox["bash-sandbox"] pkg_hooks_claude["hooks-claude"] pkg_hooks_codex["hooks-codex"] pkg_sandbox["sandbox"] svc_sandbox["ctx.sandbox
Process-sandbox seam"] pkg_sandbox_local["sandbox-local"] pkg_approval["approval"] svc_approval["ctx.approval
Approval seam"] pkg_permission["permission"] svc_permission["ctx.permission
Permission presets"] pkg_code_runtime["code-runtime"] svc_codeRuntime["ctx.codeRuntime
Code-execution seam"] pkg_code_runtime_worker["code-runtime-worker"] pkg_fs["fs"] svc_fs["ctx.fs
Filesystem provider seam"] pkg_fs_local["fs-local"] pkg_fs_policy["fs-policy"] pkg_compact["compact"] svc_compact["ctx.compact
Compaction seam"] pkg_subagent["subagent"] svc_subagents["ctx.subagents
Subagent provider registry"] pkg_subagent_spawn["subagent-spawn"] pkg_subagent_fork["subagent-fork"] pkg_subagent_acp["subagent-acp"] pkg_subagent_mock["subagent-mock"] pkg_web["web"] svc_web["ctx.web
Web access provider registry"] pkg_web_search_exa["web-search-exa"] pkg_web_search_perplexity["web-search-perplexity"] pkg_web_search_deepseek["web-search-deepseek"] pkg_web_fetch_local["web-fetch-local"] pkg_workflow["workflow"] svc_workflows["ctx.workflows
Workflow script engine"] pkg_workflow_workerthread["workflow-workerthread"] pkg_tool_workflow["tool-workflow"] pkg_acp --> svc_approval pkg_acp --> svc_userInteraction pkg_agent --> svc_agents pkg_agent_loop --> svc_agentLoop pkg_approval --> svc_approval pkg_bash --> svc_bash pkg_bash_local --> svc_bash pkg_bash_sandbox --> svc_bash pkg_code_runtime --> svc_codeRuntime pkg_code_runtime_worker --> svc_codeRuntime pkg_compact --> svc_compact pkg_compact_basic --> svc_compact pkg_fs --> svc_fs pkg_fs_local --> svc_fs pkg_llm --> svc_llm pkg_llm_deepseek --> svc_llm pkg_llm_pi_ai --> svc_llm pkg_llm_replay --> svc_llm pkg_permission --> svc_permission pkg_sandbox --> svc_sandbox pkg_sandbox_local --> svc_sandbox pkg_session --> svc_sessions pkg_session_persistence --> svc_sessionPersistence pkg_session_persistence_jsonl --> svc_sessionPersistence pkg_session_persistence_sqlite --> svc_sessionPersistence pkg_session_query --> svc_sessionQuery pkg_skill --> svc_skills pkg_skill_local --> svc_skills pkg_stdio_agent --> svc_userInteraction pkg_subagent --> svc_subagents pkg_subagent_acp --> svc_subagents pkg_subagent_fork --> svc_subagents pkg_subagent_mock --> svc_subagents pkg_subagent_spawn --> svc_subagents pkg_system_prompt --> svc_systemPrompt pkg_tools --> svc_tools pkg_user_interaction --> svc_userInteraction pkg_web --> svc_web pkg_web_fetch_local --> svc_web pkg_web_search_deepseek --> svc_web pkg_web_search_exa --> svc_web pkg_web_search_perplexity --> svc_web pkg_workflow --> svc_workflows pkg_workflow_workerthread --> svc_workflows svc_agentLoop --> pkg_agent_core svc_agents --> pkg_acp svc_agents --> pkg_agent_loop svc_agents --> pkg_invariants svc_agents --> pkg_stdio_agent svc_agents --> pkg_subagent_inprocess svc_approval --> pkg_tool_bash svc_approval --> pkg_tools svc_bash --> pkg_hooks_claude svc_bash --> pkg_hooks_codex svc_bash --> pkg_tool_bash svc_codeRuntime --> pkg_tools svc_compact --> pkg_compact_basic svc_fs --> pkg_tool_fs svc_llm --> pkg_agent_loop svc_llm --> pkg_compact_basic svc_permission --> pkg_acp svc_sandbox --> pkg_bash_sandbox svc_sessionPersistence --> pkg_acp svc_sessionPersistence --> pkg_agent_loop svc_sessionPersistence --> pkg_session_query svc_sessions --> pkg_agent svc_sessions --> pkg_agent_loop svc_sessions --> pkg_invariants svc_sessions --> pkg_session_persistence svc_sessions --> pkg_session_query svc_sessions --> pkg_subagent_inprocess svc_skills --> pkg_tool_skill svc_subagents --> pkg_tool_subagent svc_systemPrompt --> pkg_agent_loop svc_systemPrompt --> pkg_tool_fs svc_systemPrompt --> pkg_tool_web svc_systemPrompt --> pkg_tools svc_tools --> pkg_acp svc_tools --> pkg_agent_loop svc_tools --> pkg_tool_ask_user svc_tools --> pkg_tool_bash svc_tools --> pkg_tool_cordis svc_tools --> pkg_tool_fs svc_tools --> pkg_tool_skill svc_tools --> pkg_tool_subagent svc_tools --> pkg_tool_todo svc_tools --> pkg_tool_web svc_userInteraction --> pkg_acp svc_userInteraction --> pkg_stdio_agent svc_userInteraction --> pkg_tool_ask_user svc_web --> pkg_tool_web svc_workflows --> pkg_tool_workflow svc_fs -. event gate .-> pkg_fs_policy ``` | ctx key | Role | Owner | Implementations | Direct consumers | Companion plugins | Note | | --- | --- | --- | --- | --- | --- | --- | | `ctx.llm` | `seam` | [`llm`](../packages/llm/llm) | [`llm-deepseek`](../packages/llm/llm-deepseek), [`llm-pi-ai`](../packages/llm/llm-pi-ai), [`llm-replay`](../packages/support/llm-replay) | [`agent-loop`](../packages/core/agent-loop), [`compact-basic`](../packages/compact/compact-basic) | - | Adapters register provider implementations; the loop and compaction call the provider-neutral stream service. | | `ctx.sessions` | `core` | [`session`](../packages/core/session) | - | [`agent-loop`](../packages/core/agent-loop), [`agent`](../packages/core/agent), [`session-persistence`](../packages/session-persistence/session-persistence), [`session-query`](../packages/session-query/session-query), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`invariants`](../packages/support/invariants) | - | Owns append-only Session instances and emits the durable session event feed. | | `ctx.sessionPersistence` | `seam` | [`session-persistence`](../packages/session-persistence/session-persistence) | [`session-persistence-jsonl`](../packages/session-persistence/session-persistence-jsonl), [`session-persistence-sqlite`](../packages/session-persistence/session-persistence-sqlite) | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp), [`session-query`](../packages/session-query/session-query) | - | Backends persist the same SessionEvent vocabulary; apps choose a backend at composition time. | | `ctx.sessionQuery` | `seam` | [`session-query`](../packages/session-query/session-query) | - | - | - | Resolves live and optional persisted logs into one logical corpus for exact reads. | | `ctx.systemPrompt` | `core` | [`system-prompt`](../packages/core/system-prompt) | - | [`agent-loop`](../packages/core/agent-loop), [`tools`](../packages/core/tools), [`tool-fs`](../packages/fs/tool-fs), [`tool-web`](../packages/web/tool-web) | - | Collects prompt sections and model-facing tool schemas for each step. | | `ctx.tools` | `core` | [`tools`](../packages/core/tools) | - | [`agent-loop`](../packages/core/agent-loop), [`tool-ask-user`](../packages/ui/tool-ask-user), [`tool-bash`](../packages/bash/tool-bash), [`tool-cordis`](../packages/cordis/tool-cordis), [`tool-fs`](../packages/fs/tool-fs), [`tool-skill`](../packages/skill/tool-skill), [`tool-subagent`](../packages/subagent/tool-subagent), [`tool-todo`](../packages/todo/tool-todo), [`tool-web`](../packages/web/tool-web), [`acp`](../packages/ui/acp) | - | Registers capabilities, owns Code Mode transport, and routes calls through pre-policy, monotonic guards, around dispatch, post-policy, and final-result observation. | | `ctx.userInteraction` | `seam` | [`user-interaction`](../packages/ui/user-interaction) | [`stdio-agent`](../packages/ui/stdio-agent), [`acp`](../packages/ui/acp) | [`tool-ask-user`](../packages/ui/tool-ask-user), [`stdio-agent`](../packages/ui/stdio-agent), [`acp`](../packages/ui/acp) | - | UI front doors provide the active human-answer provider; tool-ask-user pauses a tool call on the provider-neutral ask() promise. | | `ctx.skills` | `seam` | [`skill`](../packages/skill/skill) | [`skill-local`](../packages/skill/skill-local) | [`tool-skill`](../packages/skill/tool-skill) | - | Merges provider skill catalogs; tool-skill renders the session-prefix catalog and loads complete skill bodies. | | `ctx.agents` | `core` | [`agent`](../packages/core/agent) | - | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`stdio-agent`](../packages/ui/stdio-agent), [`invariants`](../packages/support/invariants) | - | Owns live Agent handles and the create/resume factory seam. | | `ctx.agentLoop` | `bundle` | [`agent-loop`](../packages/core/agent-loop) | - | [`agent-core`](../packages/core/agent-core) | - | The one concrete loop plugin; extension packages depend on dsh-agent events and services, not on this package. | | `ctx.bash` | `seam` | [`bash`](../packages/bash/bash) | [`bash-local`](../packages/bash/bash-local), [`bash-sandbox`](../packages/bash/bash-sandbox) | [`tool-bash`](../packages/bash/tool-bash), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) | - | The model-facing bash tools and hook bridges consume this seam; sandboxed or remote executors replace bash-local without touching them. | | `ctx.sandbox` | `seam` | [`sandbox`](../packages/sandbox/sandbox) | [`sandbox-local`](../packages/sandbox/sandbox-local) | [`bash-sandbox`](../packages/bash/bash-sandbox) | - | Consumers hand over the exact argv they are about to spawn; same-world backends wrap it under a per-call policy and report enforcement. | | `ctx.approval` | `seam` | `approval` | [`acp`](../packages/ui/acp) | [`tools`](../packages/core/tools), [`tool-bash`](../packages/bash/tool-bash) | - | One-shot permission decisions dispatched over the `approval/request` waterfall; answerers are listeners (the ACP bridge for its own agents), absence fails closed to `unavailable`. | | `ctx.permission` | `core` | [`permission`](../packages/ui/permission) | - | [`acp`](../packages/ui/acp) | - | User-facing preset table (`workspace-write`/`danger-full-access`) bundling the sandbox-mode and approval-policy knobs; a switch writes one `permission/preset` event through to both knob events. | | `ctx.codeRuntime` | `seam` | [`code-runtime`](../packages/code-runtime/code-runtime) | [`code-runtime-worker`](../packages/code-runtime/code-runtime-worker) | [`tools`](../packages/core/tools) | - | Runs one model-written program against host-provided async bindings; backends differ by substrate and language (the tool registry consumes it for Code Mode). | | `ctx.fs` | `seam` | [`fs`](../packages/fs/fs) | [`fs-local`](../packages/fs/fs-local) | [`tool-fs`](../packages/fs/tool-fs) | [`fs-policy`](../packages/fs/fs-policy) | tool-fs executes read/write/edit through ctx.fs; fs-policy contributes observed-state checks through the fs/* event gate. | | `ctx.compact` | `seam` | [`compact`](../packages/compact/compact) | [`compact-basic`](../packages/compact/compact-basic) | [`compact-basic`](../packages/compact/compact-basic) | - | The basic backend currently consumes the pre-step event directly; a model-facing compact tool remains deferred. | | `ctx.subagents` | `seam` | [`subagent`](../packages/subagent/subagent) | [`subagent-spawn`](../packages/subagent/subagent-spawn), [`subagent-fork`](../packages/subagent/subagent-fork), [`subagent-acp`](../packages/subagent/subagent-acp), [`subagent-mock`](../packages/support/subagent-mock) | [`tool-subagent`](../packages/subagent/tool-subagent) | - | Providers implement transports; tool-subagent exposes one configured provider as a model-facing tool name. | | `ctx.web` | `seam` | [`web`](../packages/web/web) | [`web-search-exa`](../packages/web/web-search-exa), [`web-search-perplexity`](../packages/web/web-search-perplexity), [`web-search-deepseek`](../packages/web/web-search-deepseek), [`web-fetch-local`](../packages/web/web-fetch-local) | [`tool-web`](../packages/web/tool-web) | - | Search and fetch providers register into one ctx.web seam; tool-web owns the stable model-facing names. | | `ctx.workflows` | `seam` | [`workflow`](../packages/workflow/workflow) | [`workflow-workerthread`](../packages/workflow/workflow-workerthread) | [`tool-workflow`](../packages/workflow/tool-workflow) | - | One engine per context (bash shape, no named-provider registry); the worker-thread engine fans agent() calls out through ctx.subagents. | Maintenance mode: hybrid: services are discovered from Cordis declarations; interface/implementation/consumer roles are classified in `scripts/gen-doc-graphs.ts` with a completeness guard.