Field guide · Agentic engineering

The workspace
is the product.

Models are rented. Harnesses are swappable. What compounds is the place they work in: its instructions, memory, procedures, structure, and the colleagues beside them.

Seven acts · about forty-five minutes · press → to begin, G for the guide

The thesis

Give the agent a filesystem and a shell.

A model guesses when it can't look. A workspace lets it look, run, and write down what it found.

Explicit. Every input is a file you can open, diff and cite.

Open. Bash runs whatever the harness allows: search, tests, scripts.

Durable. What it learns is written back, so the next run starts ahead.

Structure and philosophy decide how it works there. That is harness engineering.

The operating model

Seven questions. One system.

Each layer answers one question an agent asks before it can do useful work.

01

Workspaces

Where does it live? Primer, policy, record and sandbox.

02

Context

What reaches the window, and how hooks make recall a reflex.

03

Second brain

How the graph is structured, read and grown.

04

Skills

How we do this kind of work, loaded on demand.

05

Structure

Which bytes it may touch, and where they go.

06

Fleets

Who else is here, and who checks whom.

07

Leadership

What all of this asks of people.

Act I

Workspaces

Where does the agent live?

I · Workspaces

A folder is not a workspace.

The difference is what survives the session.

Agent workspace

A working directory and a toolset for one agent on one task.

Useful. But context evaporates when the session ends, and the next agent starts cold.

Agentic workspace

A governed place that many agents work through.

Instructions, policy, memory, skills and a record outlive every session, so each run leaves the place a little smarter.

I · Workspaces

Six layers an agent reads before it writes.

I · Workspaces

Sandbox, harness, wire.

Three layers, three different answers. Buy the box, swap the brain, and don't bet on the wire yet.

I · Workspaces

Medallion layers live in the filesystem.

Each workspace keeps its own bronze, silver and gold as plain folders. A shared ledger records what was decided.

bronze/ Inputs as received. Append-only, hashed, never edited.

silver/ Typed and validated. Every value cites its bronze source.

gold/ Decisions and definitions the organization trusts.

Files are the agent's working memory. The ledger is the organization's.

I · Workspaces · worked example

A review system, built on the pattern.

Act II

Context

What reaches the window, and when?

II · Context

How an agent's context is built.

Everything the model knows this turn is what reached the window. The workspace decides what reaches it.

Hover any layer of the window. Each one has a source on disk, a moment it loads, and a budget.

Less guessing is the product of more grounded layers, not of a bigger model.

II · Context

Hooks turn recall into a reflex.

PrimerAsks for it
SkillKnows how
HookRuns every time
II · Context

Files first. Vectors when words diverge.

Exact names, paths, claims you can greprg + index
What this relates to, one hop outgraph links
Same idea, different words; corpora past the windowembeddings
Fresh or external stateMCP · APIs

At 1,430 entities the compiled catalog is about 260K tokens: it fits a 1M-token window, so the catalog routes and the model reads. Add vectors when vocabulary diverges or the catalog outgrows the window.

Act III

Second brain

How is knowledge read, and how does it grow?

III · Second brain

Most second brains are write-only.

0.9%

of 565 agent sessions in the seven days to 2026-10-26 loaded the knowledge graph (5 sessions). Capture is easy. Recall is the product.

measured 2026-10-26 · session telemetry

The fix is routing, not volume

Put recall on the startup path.

The primer routes to it. An intake hook surfaces matching entities. /kg load runs before planning. And when reads lag, prune production. Don't add more writers.

III · Second brain

Front matter is the API.

research/entities/pattern/llm-as-index-architecture.md---type: pattern status: entitycore_claim: "At sub-10k-entity scale the substrate fits in a 1M-context model, so the LLM IS the query…"tags: [architecture-decision, knowledge-graph, …]aliases: [kg routing, no embeddings retrieval]related: [[knowledge-graph]], [[bstack-engine]] …sources: [2026-05-21-…-synthesis, BRO-1223]---
III · Second brain

An entity is a claim with receipts.

--- # research/entities/concept/agent-harness-three-layer-split.md type: concept status: entity core_claim: "Agent harnesses split into sandbox, orchestrator and UI wire: the sandbox is buyable, the wire has no stable remote transport." sources: - url: agentclientprotocol.com/…/transports note: "Read verbatim 2026-09-26 …" scoring: {novelty: 2, specificity: 3, relevance: 3} related: [[buzz-acp-harness]], [[display-server-for-agents]] … ---
One falsifiable sentence
Read verbatim, dated
Scored before promotion
Typed links become edges
1,430entities6,076edges.mdcanonical · index of 2026-10-25
III · Second brain

The loop that makes knowledge readable.

Memory holds facts about the owner. The graph holds claims about the world. The ledger holds what is in flight.

III · Second brain

Insight hardens into mechanism.

Promote on the third instance, with a concrete mechanism, an invariant and a failure mode. Name what the new rule retires.

Act IV

Skills

How is this kind of work done here?

IV · Skills

A skill is a procedure,
not a prompt.

skills/knowledge/kg/ ├─ SKILL.md description is the router ├─ scripts/ deterministic core └─ evals/ routing + behavior tests --- name: kg description: Load graph context for a topic… USE WHEN … NOT FOR … ---
IV · Skills

Skill, CLI, MCP.

One knows. One does. One reaches.

Repeatable judgment and stepsSkill
Deterministic, local, testable workCLI
Remote system, auth, shared across harnessesMCP server
A one-offJust ask

A skill that drives a small CLI beats a wide MCP surface: fewer tools in context, and a core you can test.

IV · Skills

Author once. Fan out. Ration hard.

115authored
23categories
31harness folders
Act V

Structure

Which bytes may the agent touch?

V · Structure

One place, many repos.

workspace/ governance repo├─ AGENTS.md ≡ CLAUDE.md one primer, every harness├─ .control/ policy · initiatives · asks├─ roles/ lenses: context per kind of work├─ skills/ canonical skills, own repo├─ research/entities/ the graph, as markdown├─ docs/ sessions · plans · handoffs · ADRs├─ apps/ core/ work/ … product repos, own CI└─ .worktrees/ one per task, disposable
V · Structure

One writer per tree.

Parallel agents never share a checkout. They share main, through review.

01Branch is the first action
02Reviewers read. They never write
03A live thread's worktree is the thread
04Unfinished work becomes a draft PR
05Janitor after merge, dry-run first
Act VI

Fleets

Who else is here, and who checks whom?

VI · Fleets

Roles, not agents.

VI · Fleets

Spawn, reuse, or hand off.

Independent of what I know?
Spawn a child task in its own worktree.
Needs my context?
Continue here, or fork the thread.
Outlives this context window?
Write a persistent brief with stop conditions.
Only the owner can decide?
File an ask: context, options, a recommendation and a safe default.
Handoffnarrative for the next agent
Handbackmessage for the human
Briefloop state across contexts
Aska decision, with its context
Receiptevidence it actually works
VI · Fleets

Governance that scales with the fleet.

PaceFrom measured capacity, not hope
ReviewThe writer cannot certify its own work
PolicyExecutable gates. Prose is only advice
SensorsObserve and file. Agents act
Act VII

Leadership

What does this ask of people?

VII · Leadership

The unit of work is now a loop.

When an attempt costs minutes, making gets abundant and deciding gets scarce.

Every question is something you can start today.

Every repeated task is something you can automate or improve.

Every piece of work leaves the system better: a note, a skill, a check.

The question moves from “can I do this?” to “should this exist, and how will I know it's right?”

VII · Leadership

Everyone leads a fleet.

What each person brings to their fleet is taste and judgment: knowing what good looks like, and deciding what to accept.

VII · Leadership

Attention is the new ration.

Reversible drafts, research, branches: act and note it.

Costly long compute, many iterations: only inside a budget.

Irreversible or external spend, publish, merge outside policy, contact: a yes first, every time.

The measure of an autonomous system isn't how much it does without you. It's how precisely it calls you.

VII · Leadership

Goalposts teach waiting. Bars rise in the open.

People learn to wait when proposals get overridden, the leader decides anyway, the bar moves silently, or a failed attempt costs more than a passive miss.

Make everything queryable: decisions, standards and why they changed live in the same shared graph that people and agents read.

Epilogue

Better agents come from better harnesses.

Epilogue

Twenty primitives. One loop.

01

Give agents a place before you give them more autonomy.

02

Make the graph readable at intake, or stop writing to it.

03

Scale with roles, isolation and review. Not with more prompts.

The workspace is the product.
Agent workspaces
AGENT WORKSPACES · PRESENTER00:00

Now ·

Notes

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Then

Keys

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