A visual field guide

DeepSeek Harness Atlas

Skills, architecture, and decisions—mapped.

A development timeline and roadmap for DeepSeek Harness.

Evolution Timeline

One chronological trunk, one node per decision. Cards branch left and right; each Note can switch between English and Chinese.

1266 bilingual pairs1216 implemented8 rejected42 proposed

Archived nodes stay green because their decisions shipped. They are frozen historical records, not current authority.

Implemented / ArchivedRejectedProposed

2026-06-11

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Evolution Timeline

Provider-neutral content-block vocabulary owned by dsh-llm

Custom typed tool-schema DSL instead of schemastery

Microkernel — extension via Cordis event taxonomy, one concrete loop

Runtime arg validation at the model boundary

Structured error taxonomy

Tool schemas are part of the system-prompt assembly

Doc-sync enforcement

Mechanical quality gates over prose guidelines

tsdown for JS bundling instead of dumble

Vendor Cordis as source, not npm dependencies

Property-based testing for protocol-shaped code

Source-owned session immutability

Event-sourced sessions with derived message history

API extractor reports

Supply chain checks and vendor drift verification

Deterministic tests, the replay invariant fixture, and race stress

Mutation testing as the coverage counterweight

Capability seams — Service Definition / Service Provider / Consumer roles

Two LLM adapters as a design-verification twin

Session persistence as an abstract service over the existing `SessionEvent`

Agent Client Protocol (ACP) support — drive the coding agent from external editors

Multiplex concurrent ACP sessions over one connection

Every session event is enclosed in a turn

PTC mode — the model writes TypeScript against the tool registry

pnpm as the package manager instead of Yarn 4

Runtime schemas for the event vocabulary (Zod vs the merge-extensible-map pattern)

Filesystem capability seam — ctx.fs, local backend, and model-facing filesystem tools

Filesystem tool schemas — model-facing read/write/edit shapes

TSC-first build and one compiler ownership

Agent lifecycle and ownership contracts

Shared persistence write coordinator

Rich ACP bash rendering — the terminal card via the `_meta` convention

Compaction as a capability seam (abstract contract + basic backend)

Markdown cross-link validity linting

Session surface — an ordered projection over the event log

Drop the mutable session summary

ACP snapshot tests — record-once / replay-deterministic

Real-API e2e in CI against the external DeepSeek API

Branded IDs everywhere they belong

Extract example apps into packages

The background job runtime (`ctx.jobs`) and generic task control tools

Reorganize packages into a modular hierarchy

Classify Agent Notes by kind via path-encoded subdirectories

Subsystems catalog and the `ts type-equiv` drift gate

Generated cordis events + services catalog

Fold trace-only session facts into load-bearing events

Drop the unconsumed `llm/adapter-change` event

Drop unconsumed assembled LLM convenience surfaces

Prune dead methods from the persistence seam

Keep one public stop primitive

Stop mirroring durable boundaries as agent events

Use `session.jsonl` as the only snapshot session-log artifact

Unify the agent id and the session id

Discover package inventories instead of maintaining static lists

Drop durable step boundary events

Fold the persistence interface into dsh-session

Truncate interrupted final turns on load

Mandatory `User-Agent` attribution for provider requests

Subagent capability seam

Bounded recovery for transient LLM request failures

ACP subagent backend (out-of-process delegation)

Persist the seed boundary so fork-child replay routes correctly

Record fork and mixed spawn+fork snapshot scenarios

Per-session snapshot replay for nested agents

Workspace context instruction files

Web capability seam - stable tools over multiple providers

Ask-user question capability

Make `dsh-fs-observation-policy` an event-gate plugin, not a method interface

Split the filesystem seam — provider text mutations plus the `dsh-fs-observation-policy` plugin

The `todo_write` tool — model task list as event-sourced session state

stdin + extra env on the bash seam

dsh-hooks-claude-code + dsh-hooks-codex — the Claude Code / Codex hook bridges

dsh-hook-protocol — the shared Claude Code / Codex hook wire-protocol core

Interception extension points — the typed-Decision surface a hook programs against

SessionStore fork API

Subagent lifecycle enrichment — lastAssistantMessage (observe-only)

Event-domain semantics — session is the fact log, agent is the live event channel

Pre-tool input rewrite — a consistent design

Resolve filesystem paths against the caller's session cwd