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.

739 bilingual pairs702 implemented11 rejected26 proposed

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

Implemented / ArchivedRejectedProposed

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Evolution Timeline

Custom typed tool-schema DSL instead of schemastery

Tool schemas are part of the system-prompt assembly

Doc-sync enforcement

tsdown for JS bundling instead of dumble

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

Source-owned session immutability and dev-mode invariants

Event-sourced sessions with derived message history

Microkernel — extension via Cordis event taxonomy, one concrete loop

Runtime arg validation at the model boundary

Structured error taxonomy

Mechanical quality gates over prose guidelines

Vendor Cordis as source, not npm dependencies

Property-based testing for protocol-shaped code

API extractor reports

Architectural conformance — dependency rules and the adapter kit

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

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

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

Multiplex concurrent ACP sessions over one connection

Every session event is enclosed in a turn

Code 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

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

Agent lifecycle and ownership contracts

Session surface — an ordered projection over the event log

Shared persistence write coordinator

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

Markdown cross-link validity linting

Drop the mutable session summary

ACP snapshot tests — record-once / replay-deterministic

Real-API e2e in CI against the external DeepSeek API

Extract example apps into packages

Reorganize packages into a modular hierarchy

Generated cordis events + services catalog

Drop the unconsumed `llm/adapter-change` event

Drop unconsumed assembled LLM convenience surfaces

Prune dead methods from the persistence seam

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

Branded IDs everywhere they belong

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

Classify Agent Notes by kind via path-encoded subdirectories

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

Fold trace-only session facts into load-bearing events

Keep one public stop primitive

Stop mirroring durable boundaries as agent events

Unify the agent id and the session id

Discover package inventories instead of maintaining static lists

Persist assembled assistant messages, not stream chunks

Drop bash full-output spill files

Drop durable step boundary events

Fold the persistence interface into dsh-session

Truncate interrupted final turns on load

Bounded recovery for transient LLM request failures

Mandatory `User-Agent` attribution for provider requests

Subagent capability seam

Record fork and mixed spawn+fork snapshot scenarios

ACP subagent backend (out-of-process delegation)

Persist the seed boundary so fork-child replay routes correctly

Per-session snapshot replay for nested agents

Web capability seam - stable tools over multiple providers

Workspace context instruction files

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

Subagent lifecycle enrichment — lastAssistantMessage (observe-only)

stdin + extra env on the bash seam

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

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