H
Howardism
Howardism · Vol. 03Plate II · No. 02

Agent Systems, in order.

Notes23DomainAgent SystemsOpen Qs60Newest21 Jul 2026Oldest10 Apr 2026

Agent harnesses, loop engineering, and scaffolding for LLM systems.

Map of Content for the agent-systems domain — 23 concepts. Harness engineering, agent loops and orchestration, context management, protocols and tool infrastructure (MCP, app servers), and subagents. Curated entry point; see Home for all domains.

  • Agent Context Files — The cross-vendor markdown-as-control-plane pattern: repo-versioned plaintext (CLAUDE.md / AGENTS.md / SOUL.md / WORKFLOW.md / SPEC.md /.cursorrules) that configures agent behavior, split by role across project / personality / workflow / spec layers
  • Agent Harness Engineering — Patterns for scaffolding long-running LLM agents: environment design, progressive context disclosure, mechanical architecture enforcement, agent code review
  • Agent Loop Pattern/loop (cron-scheduled) and Ralph Wiggum (backlog-draining) loops as next-generation agent primitive; AFK execution, parallel fan-out, "loops are the future"
  • Agent-Native Infrastructure — The world is still built for humans and must be rewritten for agents; "what do I copy-paste to my agent?"; sensors/actuators; agent-to-agent representation
  • Agent Quality Flywheel — Google's eval-fix loop packaged as a skill your coding agent drives: Build & Test → Ship & Monitor → Learn & Refine, expanded into five stages (prepare data / run inference / grade / analyze failures / optimize); plain-language worry in, metric choice and before/after deltas out; synthetic User Simulator bootstraps, production OTel traces sharpen
  • Build for the Next Model — Prototype the thing that almost works, not the thing that already works: bet that the next concrete model release (not a far-future AGI) fixes what your engineering can't; Claude Design's Opus 4.7 payoff and OpenAI's 'the February Codex app would have failed in November' are the cleanest cases — same product shape, different-intelligence release, different outcome
  • Claude Code Auto Mode — Claude Code permission mode using a classifier to auto-approve safe tool calls and block risky ones; middle ground between default and --dangerously-skip-permissions
  • Claude Code Best Practices (hub) — Anthropic's guide to effective Claude Code usage: context management, verification-driven development, explore→plan→code workflow, environment config
  • Client-Side Agent Optimization — AgentOpt's framing of developer-controlled agent optimization (model-per-role, budget, routing) as distinct from server-side serving; the combo abstraction; 13–32× cost gaps between best/worst combinations
  • Codex App Server Protocol — JSON-RPC stdio protocol for headless Codex sessions: initialize/initialized/thread-start/turn-start handshake, continuation turns reuse thread_id, dynamic tool calls for token-isolated tool injection
  • Context Window Smart Zone (hub) — Smart zone vs dumb zone (Dex Hardy / Matt Pocock): quadratic attention scaling, ~100K marker independent of advertised context; clear-and-restart > compaction; status-line token counting as essential discipline
  • Deep Modules for Agents — Ousterhout deep-vs-shallow modules applied to agent-friendly codebases; push-vs-pull instruction delivery; reviewer in fresh context; Sandcastle three-agent pattern
  • Deep Research Agents — Agentic systems that decompose a complex query, iteratively search diverse sources, and synthesize a structured, cited report — distinct from single-shot QA; DRACO shows orchestration (Perplexity) beats the bare base model with tools, and factual accuracy is the weak axis
  • Failures That Look Like Success — The quiet agent-failure class where everything reads fine — confident answer, plausible plan, even correct internal state — but the user-facing outcome is wrong; Google's flywheel demos caught agents echoing stale values despite correct memorize calls and silently skipping self-report instructions; detectable by trace-level rubrics, not output skims
  • Harness Shrinkage as Models Improve (hub) — Prompt scaffolding shrinks each model release; Cat Wu's pruning discipline; Boris Cherny "100 lines of code a year from now" claim; mechanical verification stays load-bearing
  • Latent vs. Deterministic Space — Garry Tan's diagnostic for agent-system bugs: computation lives in two places — latent space (the LLM: taste, judgment, vague-intent interpretation, steered by markdown) and deterministic space (generated code, external state) — and most AI-engineering failures are computation happening on the wrong side
  • LLM-as-Compiler Knowledge Base — Karpathy's architecture: LLM incrementally compiles raw docs into a persistent interlinked wiki, replacing RAG with a 4-phase ingest→compile→query→lint pipeline
  • Loop Engineering — Replacing yourself as the agent's prompter by designing the system that prompts it: a recursive-goal loop built from five product-native primitives (automations, worktrees, skills, connectors, sub-agents) plus external memory; tool-agnostic across Codex and Claude Code; the leverage point moves from prompt-crafting to loop-design
  • MCP and Computer Use — Anthropic's two complementary connector mechanisms: MCP for structured programmatic access (Salesforce/Drive/Gmail/Slack/Figma + niche industry systems); computer use as the GUI-driving catchall when no MCP exists; Boris Cherny's "to the model, it's just tokens"
  • Optimizer–Evaluator Decoupling — The architectural rule in eval-fix loops that whatever proposes a fix (coding agent, automated optimizer, human) never grades it — an independent evaluation service scores the result, because an optimizer that grades its own work learns to game the metric instead of improving the agent
  • Parallel Agent Orchestration — OpenAI Codex study's concurrency + runtime margins: the intensive-user workflow where a human oversees a team of agents rather than doing the work directly — 28.6% of OpenAI users peaked at 5+ concurrent agents in a week (vs ~64-67% of external users running zero concurrent), and p99 OpenAI users ran ~71 agent-hours/day (up 88% since April 2026); the threaded interaction model lets one person delegate, monitor, and review many simultaneous streams — first hard numbers behind founder-as-agent-orchestrator
  • Repository Exploration Subagent — FastContext's thesis that repository exploration (read/search/localization) should be decoupled from solving into a dedicated read-only subagent that issues parallel tool calls and returns compact file-line citations, keeping the solver's context clean — cutting main-agent tokens up to 60% and lifting SWE-bench resolution up to 5.5%
  • Ticket-Driven Agent Orchestration — The inversion that makes Symphony work: tickets as units of work (not sessions/PRs), DAG dependencies, agent-extensible work graph, "objectives not transitions"

Open questions 60 open

  • Agent Context Files
    • How should context files and bounded memory files interact when they disagree? Memory is lossy and cache-delayed; the context file is authoritative but static. Which wins, and when?
  • Agent Harness Engineering
    • At what codebase scale does the AGENTS.md-as-table-of-contents approach need to be replaced with more sophisticated context routing?
    • How generalizable are these web-app-focused findings to other domains (scientific research, financial modeling)?
  • Agent Quality Flywheel
    • Both demo cycles fixed agents with *instruction-level* bugs and showed large one-cycle gains. What does the loop look like on failures that need tool, memory, or architecture changes — does "several iterations before metrics move" dominate in practice?
    • The custom rubric is authored by the same coding agent that will later propose fixes. Metric *choice* is upstream of grading — does decoupling need to extend to who defines the metric, not just who scores it?
    • Synthetic User Simulator scenarios bootstrapped the whole first cycle. How much of the 21%→5% delta survives on real-traffic distributions (the representativeness gap [[production-sourced-evaluation]] names)?
  • Build for the Next Model
    • How do you tell a "wait for the model" gap from a durable-harness gap *before* the next release? Get it wrong and you either ship vaporware or build a crutch you'll delete.
    • The bet depends on a reliable release cadence and a forecastable capability curve ([[task-time-horizon-scaling]]). What happens to "build for the next model" if model improvement stalls (the [[recursive-self-improvement|stalled-but-diffused]] future)?
    • Does the strategy generalize outside frontier labs, who have privileged visibility into the next model? An external team is betting on a release it can't see.
  • Claude Code Auto Mode
    • What false-positive rate does the classifier have on routine-but-aggressive refactors (e.g., large-file renames, `rm` of build artifacts)?
    • How well does the classifier generalize to custom tools / MCP servers where it lacks environment context?
    • Is the classifier's decision boundary documented/stable enough for security-sensitive orgs to certify, or is it effectively a black box whose behavior drifts with updates?
    • Does extending auto mode to API users change its calibration — is the classifier retrained for automation-heavy use, or held constant?
    • Compared to OS-level sandboxing (mentioned in [[claude-code-best-practices]] alongside auto mode), what's the defense-in-depth story? When should both be layered?
  • Claude Code Best Practices
    • What's the optimal CLAUDE.md length before instructions start getting lost? Is there a measurable threshold?
    • How does the Writer/Reviewer pattern compare to agent-to-agent review (as in OpenAI's Codex workflow)?
    • When does subagent overhead exceed the benefit of context isolation?
  • Client-Side Agent Optimization
    • How does combination-level optimization interact with continual model releases? If Claude Opus 4.7 ships next month, does the full Pareto frontier need re-running, or do warm-started bandits adapt cheaply?
    • At what pipeline depth does the combinatorial search become intractable even for Arm Elimination? The paper tests up to ~81 combinations; production pipelines with 5+ roles and 10+ candidate models each blow past that.
    • Does the "weak planner + strong solver" pattern generalize, or is it specific to HotpotQA's delegation dynamic? Recommender-critic, drafter-editor, and retriever-generator topologies might invert.
    • What's the right way to re-evaluate when the tool environment changes? AgentOpt assumes fixed tools — adding or removing a tool potentially invalidates the whole frontier.
    • Is there a cheap per-call classifier that can predict which combination will win on a given query, avoiding combo-level evaluation entirely?
  • Codex App Server Protocol
    • How does the App Server protocol compare in detail to MCP? Both expose tools to a model, but App Server is *inside* the Codex runtime while MCP is *outside*. When does each win?
    • Is there a public schema registry so external orchestrators can target specific App Server versions without `generate-json-schema`?
    • The "dynamic tool calls (experimental)" caveat — what's the stability roadmap? Symphony depends on this for its security model.
    • How well does the protocol handle multi-modal turns (image inputs, screenshot attachments)? The spec is text-focused.
    • Is there an analogous protocol on the Claude side, or is Claude's equivalent exclusively the Agent SDK + tool-use API? Comparing the two would clarify when "drive an existing CLI" beats "build on the SDK."
  • Context Window Smart Zone
    • Does the smart-zone marker scale with model size, or is it bounded by attention architecture? Pocock observes "the dumb zone has become less dumb lately" but pegs it at 100K through 2026.
    • How should harnesses surface remaining smart-zone budget to the user — token count, percentage, or a richer signal?
  • Deep Modules for Agents
    • How big is "deep enough"? Pocock's example modules are several hundred LOC; Ousterhout's textbook examples are larger. There's a sweet spot; not articulated.
    • For ports/adapters codebases, does the deep-module advice transfer cleanly? The "small interface" is the port; the "large behavior" is the adapter. Probably yes, but not exercised in source.
    • Refactor cost vs benefit: when is "improve-code-base-architecture" worth running on a working repo?
  • Deep Research Agents
    • DRACO grades single-turn interactions only. How much of real deep-research value is in the multi-turn loop (clarifying questions, follow-ups) that the benchmark doesn't yet measure?
    • Factual accuracy is the weak axis everywhere — is the fix better retrieval, better verification-in-the-loop, or a tool-grounded check the way Lean grounds proof search?
  • Failures That Look Like Success
    • Is "internal state correct, final message stale" a general LLM-agent failure signature (state/utterance divergence) or an artifact of session-state architectures like ADK's? A cross-framework tally would tell.
    • What fraction of production agent failures are silent-contract violations vs. loud errors? The 14/15 and 3/4 numbers are demo-sized; telemetry-scale data ([[production-sourced-evaluation]]) could ground the class.
  • Harness Shrinkage as Models Improve
    • Does *all* prompt scaffolding eventually migrate into the model, or does some remain — e.g. organization-specific style, security rules, brand voice?
  • Latent vs. Deterministic Space
    • Tan asserts the "wrong side" diagnosis covers most AI-engineering bugs. Does any incident/failure taxonomy (agent postmortems, eval failure analyses) actually classify failures by computation-locus, and what fraction lands in each side?
  • LLM-as-Compiler Knowledge Base
    • At what scale does the no-vector-database approach break down? Karpathy's ~100 articles fit in context, but what about 1,000+?
    • How to handle conflicting information across sources during compilation?
    • What's the optimal granularity for concept articles — one concept per article, or clustered by theme?
    • How effective is the synthetic training data → fine-tuning pipeline in practice?
  • Loop Engineering
    • Osmani's cost caveat is unquantified: at what token budget does a continuously-running loop stop paying for itself, and how do you instrument that? (Cf. [[agent-loop-pattern]]'s "who owns the budget when the model schedules its own loops.")
    • If `/goal`'s stop-check is itself a model, what verifies the verifier? The maker/checker split pushes the trust problem up a level, not away.
  • MCP and Computer Use
    • MCP security model: as the playbook prescribes wiring MCP into Salesforce, Gmail, Calendar for solo founders, the attack surface scales with adoption. **Now addressed** by [[zero-trust-for-ai-agents]] (tool poisoning, rug pulls, the first in-the-wild malicious MCP server) — see "MCP as a security surface" above. Open residual: how does a solo founder realistically *run/host and self-sign every MCP server* the framework recommends, given that the appeal of MCP was zero-integration-effort? **Sharpened by [[mcp-tool-poisoning|ShareLock]]:** the cheaper alternative to self-hosting — *scan the tool descriptions with a guard model* — is information-theoretically defeated by threshold fragmentation, so the lightweight mitigation doesn't hold and the burden falls back on run-your-own-server or downstream action-layer authorization. **And [[mcp-tool-poisoning|Agentjacking]] shows run-your-own-server *itself* isn't sufficient:** when the server is a legitimate observability platform relaying attacker-injected data (fake Sentry errors), self-hosting/vetting the server catches nothing — the untrusted input rides in on its data, so the residual burden falls squarely on the downstream data/action layer (provenance tracking + an out-of-band action gate), not on server hygiene.
    • How does Cowork's computer-use guardrail compare to Claude Code's auto-mode classifier? Different deployment context, possibly different risk profile.
  • Optimizer–Evaluator Decoupling
    • Does decoupling need to extend upstream to metric *design*? An optimizer that authors its own rubric has a subtler channel to game than one that merely reads scores.
    • How much independence is enough — different model family, different vendor, different modality of check (model judge vs. compiled test vs. production telemetry)?
  • Parallel Agent Orchestration
    • Summed-overlap runtime can exceed 24h/day — it measures *agent* effort, not *human* attention. What is the human's actual oversight load per concurrent agent, and where does it saturate ([[ai-brain-fry]])? **Sharpened:** [[configurable-human-participation|HAS-Bench]] reframes the *shape* rather than measuring the load — in a controlled (LLM-simulated) benchmark the value of human input is configuration-dependent and *non-monotonic* (a right-timing / right-channel / right-authority sweet spot; more agency brings diminishing and sometimes negative returns), so per-agent oversight is likely a returns-curve with a peak, not a linear cost that hits a wall — but it is single-human, single-task, so it does not measure real concurrent-oversight load.
    • Concurrency is measured over one week. Is 5+-agent management a stable practice or a burst around specific large tasks?
  • Repository Exploration Subagent
    • **Does the gain survive better main models?** The same-model-exploration result suggests the architectural benefit is somewhat model-independent, but the trained-explorer margin may erode as frontier models get cheaper and better at staying in their smart zone unaided. The bitter-lesson question is unresolved.
    • **Prune vs. don't-pollute.** SWE-Pruner removes context after the fact; FastContext avoids accumulating it. Are these complementary (prune the solver *and* delegate exploration) or substitutes? Not tested together.
    • **How small can the explorer go?** The authors flag 1.7B / 0.6B as future work — if the recipe holds, the explorer becomes nearly free and the architecture dominates.
    • **Generality beyond Mini-SWE-Agent.** Only one (deliberately minimal) main-agent scaffold is tested; richer harnesses with their own memory/subagent orchestration may already capture part of the benefit or interact differently.
    • **Patch-derived reward leakage.** Training the explorer's reward on the gold patch's file/line ranges risks overfitting to where fixes *landed* rather than where evidence *lives*; the F1-vs-recall behavior partly mitigates this, but the proxy is imperfect.
  • Ticket-Driven Agent Orchestration
    • What's the right granularity for ticket size when the unit is "what one agent does in one workspace"? The post implies "much larger units of work" become viable, but how does that interact with the `agent.max_turns` limit (default 20)?
    • How do you prevent a ticket-extension cascade when agents file follow-up tickets liberally? Is the only governance check human triage at the `Todo`-state queue?
    • Does this pattern generalize to non-software work (research, ops, content)? The DAG dependency model and prompt-as-policy file should transfer; the per-issue workspace doesn't obviously.
    • When an agent gets a ticket "completely wrong" (mentioned in the post), how is the lesson fed back into the system? Symphony's answer is "add guardrails and skills" — what's the institutional process for that?
    • How does ticket-driven orchestration interact with sprint planning / OKRs / roadmap work that operates on aggregates of tickets? Does the abstraction collapse when tickets are scoped that small?