deepseek-harness/docs/capability-seams.md

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.

flowchart LR
  pkg_llm["llm"]
  svc_llm["ctx.llm<br/>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<br/>In-memory session store"]
  pkg_agent["agent"]
  pkg_session_persistence["session-persistence"]
  pkg_subagent_inprocess["subagent-inprocess"]
  pkg_invariants["invariants"]
  svc_sessionPersistence["ctx.sessionPersistence<br/>Durable session persistence seam"]
  pkg_session_persistence_jsonl["session-persistence-jsonl"]
  pkg_session_persistence_sqlite["session-persistence-sqlite"]
  pkg_acp["acp"]
  pkg_system_prompt["system-prompt"]
  svc_systemPrompt["ctx.systemPrompt<br/>System prompt assembly registry"]
  pkg_tools["tools"]
  pkg_tool_fs["tool-fs"]
  pkg_tool_web["tool-web"]
  svc_tools["ctx.tools<br/>Tool registry and execution waterfall"]
  pkg_tool_ask_user["tool-ask-user"]
  pkg_tool_bash["tool-bash"]
  pkg_tool_cordis["tool-cordis"]
  pkg_tool_subagent["tool-subagent"]
  pkg_tool_todo["tool-todo"]
  pkg_user_interaction["user-interaction"]
  svc_userInteraction["ctx.userInteraction<br/>Human question/answer seam"]
  pkg_stdio_agent["stdio-agent"]
  svc_agents["ctx.agents<br/>Agent registry"]
  svc_agentLoop["ctx.agentLoop<br/>Concrete loop driver"]
  pkg_agent_core["agent-core"]
  pkg_bash["bash"]
  svc_bash["ctx.bash<br/>Bash executor seam"]
  pkg_bash_local["bash-local"]
  pkg_hooks_claude["hooks-claude"]
  pkg_hooks_codex["hooks-codex"]
  pkg_code_runtime["code-runtime"]
  svc_codeRuntime["ctx.codeRuntime<br/>Code-execution seam"]
  pkg_code_runtime_worker["code-runtime-worker"]
  pkg_fs["fs"]
  svc_fs["ctx.fs<br/>Filesystem provider seam"]
  pkg_fs_local["fs-local"]
  pkg_fs_policy["fs-policy"]
  pkg_compact["compact"]
  svc_compact["ctx.compact<br/>Compaction seam"]
  pkg_subagent["subagent"]
  svc_subagents["ctx.subagents<br/>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<br/>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<br/>Workflow script engine"]
  pkg_workflow_workerthread["workflow-workerthread"]
  pkg_tool_workflow["tool-workflow"]
  pkg_acp --> svc_userInteraction
  pkg_agent --> svc_agents
  pkg_agent_loop --> svc_agentLoop
  pkg_bash --> svc_bash
  pkg_bash_local --> 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_session --> svc_sessions
  pkg_session_persistence --> svc_sessionPersistence
  pkg_session_persistence_jsonl --> svc_sessionPersistence
  pkg_session_persistence_sqlite --> svc_sessionPersistence
  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_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_sessionPersistence --> pkg_acp
  svc_sessionPersistence --> pkg_agent_loop
  svc_sessions --> pkg_agent
  svc_sessions --> pkg_agent_loop
  svc_sessions --> pkg_invariants
  svc_sessions --> pkg_session_persistence
  svc_sessions --> pkg_subagent_inprocess
  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_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	llm-deepseek, llm-pi-ai, llm-replay	agent-loop, compact-basic	-	Adapters register provider implementations; the loop and compaction call the provider-neutral stream service.
ctx.sessions	core	session	-	agent-loop, agent, session-persistence, subagent-inprocess, invariants	-	Owns append-only Session instances and emits the durable session event feed.
ctx.sessionPersistence	seam	session-persistence	session-persistence-jsonl, session-persistence-sqlite	agent-loop, acp	-	Backends persist the same SessionEvent vocabulary; apps choose a backend at composition time.
ctx.systemPrompt	core	system-prompt	-	agent-loop, tools, tool-fs, tool-web	-	Collects prompt sections and model-facing tool schemas for each step.
ctx.tools	core	tools	-	agent-loop, tool-ask-user, tool-bash, tool-cordis, tool-fs, tool-subagent, tool-todo, tool-web, acp	-	Registers tool definitions, exposes schemas to the prompt, and routes calls through tools/pre-execute and tools/post-execute.
ctx.userInteraction	seam	user-interaction	stdio-agent, acp	tool-ask-user, stdio-agent, acp	-	UI front doors provide the active human-answer provider; tool-ask-user pauses a tool call on the provider-neutral ask() promise.
ctx.agents	core	agent	-	agent-loop, acp, subagent-inprocess, stdio-agent, invariants	-	Owns live Agent handles and the create/resume factory seam.
ctx.agentLoop	bundle	agent-loop	-	agent-core	-	The one concrete loop plugin; extension packages depend on dsh-agent events and services, not on this package.
ctx.bash	seam	bash	bash-local	tool-bash, hooks-claude, hooks-codex	-	The model-facing bash tools and hook bridges consume this seam; sandboxed or remote executors can replace bash-local.
ctx.codeRuntime	seam	code-runtime	code-runtime-worker	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	fs-local	tool-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	compact-basic	compact-basic	-	The basic backend currently consumes the pre-step event directly; a model-facing compact tool remains deferred.
ctx.subagents	seam	subagent	subagent-spawn, subagent-fork, subagent-acp, subagent-mock	tool-subagent	-	Providers implement transports; tool-subagent exposes one configured provider as a model-facing tool name.
ctx.web	seam	web	web-search-exa, web-search-perplexity, web-search-deepseek, web-fetch-local	tool-web	-	Search and fetch providers register into one ctx.web seam; tool-web owns the stable model-facing names.
ctx.workflows	seam	workflow	workflow-workerthread	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.