deepseek-harness/docs/capability-seams.md

<!-- Generated by scripts/gen-doc-graphs.ts - do not edit by hand.
     Run `pnpm run gen-doc-graphs` to regenerate. -->

# 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<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_bash["tool-bash"]
  pkg_tool_subagent["tool-subagent"]
  pkg_tool_todo["tool-todo"]
  svc_agents["ctx.agents<br/>Agent registry"]
  pkg_stdio_agent["stdio-agent"]
  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_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_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_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
  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_bash
  svc_tools --> pkg_tool_fs
  svc_tools --> pkg_tool_subagent
  svc_tools --> pkg_tool_todo
  svc_tools --> pkg_tool_web
  svc_web --> pkg_tool_web
  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), [`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) | - | Backends persist the same SessionEvent vocabulary; apps choose a backend at composition time. |
| `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-bash`](../packages/bash/tool-bash), [`tool-fs`](../packages/fs/tool-fs), [`tool-subagent`](../packages/subagent/tool-subagent), [`tool-todo`](../packages/todo/tool-todo), [`tool-web`](../packages/web/tool-web), [`acp`](../packages/ui/acp) | - | Registers tool definitions, exposes schemas to the prompt, and routes calls through tools/pre-execute and tools/post-execute. |
| `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) | [`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 can replace bash-local. |
| `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. |

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.