Agentic Wikiwiki

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Reference pages on managing AI agents as a team. Every page is fact-checked before it ships and carries its own verification trail.

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Reference

Concepts, techniques, tools, models, and benchmarks.

Concepts5

  • Agent HarnessThe software shell that turns a model into an agent: the loop feeding it context and executing its tool calls, the tool interfaces, context management, and the permission boundary. The model reasons; the harness decides what it sees, touches, and how its work is verified.
  • Benchmark ContaminationLeakage of evaluation benchmark data into a model's training corpus, so scores reward memorization instead of capability. Covers documented leakage pathways, measured prevalence, and three detection families: n-gram overlap, membership inference, in-context disruption.
  • Context WindowAll the text an LLM can reference while generating a response, including the response itself — the model's working memory for one inference pass, distinct from its training data and degrading in reliability as it fills.
  • Evaluation AwarenessA model's capacity to detect that it is being evaluated rather than deployed, and the risk it behaves differently as a result. 2025 frontier models classify eval-vs-deployment transcripts near human level (AUC 0.83 vs 0.92), threatening benchmark and audit validity.
  • SubagentAn agent spawned by a parent agent to run a delegated task in its own isolated context window, with its own prompt, tool access, and often model; the parent stays in control and receives only the returned result.

Techniques3

  • Best-of-N SamplingGenerating N candidate responses and letting a verifier or reward model pick one — buying task success with inference compute instead of retraining. Gains scale with N only as far as the selector holds: against an imperfect reward model, true quality follows an inverted-U.
  • Context CompactionAutomatically summarizing an agent's older conversation when it nears the context window limit so long-running tasks can continue — continuity bought at the price of fidelity: high-level state survives, exact specifics silently drop.
  • Goal ModeGiving an agent a persistent, verifiable completion condition and letting the harness start new turns on its own until the check passes — replacing per-step prompting with condition-checked autonomy, at the price of unattended token burn when the condition is written loosely.

Harness patterns3

  • Agent-as-a-JudgeHarness pattern where the evaluator is itself an agent: a tool-equipped judge inspects the evaluated agent's workspace and trajectory and grades every requirement — step-level evaluation at roughly 2% of a human panel's cost on DevAI.
  • LLM-as-JudgeHarness pattern that delegates evaluation to a model: a judge LLM grades or ranks another model's or agent's output where no mechanical correctness check exists, trading human-eval fidelity for scale at the cost of position, verbosity, and gaming biases.
  • Multi-Agent DebateHarness pattern where multiple LLM agents answer a task independently, then read peers' reasoning and revise over rounds toward a common answer. Verified gains on reasoning benchmarks; degrades toward majority voting under correlated errors, at multiplied inference cost.

Tools2

  • Claude CodeAnthropic's agentic coding tool: an agent harness pairing Claude models with built-in tools, context management, permissions, and sandboxing. Runs interactively (CLI, IDE, web) or headless (print mode, Agent SDK). Described as of v2.1.206 (2026-07-10).
  • cmuxOpen-source native macOS terminal app by Manaflow for supervising parallel terminal-based coding agents: per-workspace notifications, status sidebar, embedded scriptable browser, and a Unix socket API. Described as of v0.64.17 (2026-06-23).

Models12

  • Claude Fable 5Anthropic's first generally available Mythos-class model (`claude-fable-5`, GA 2026-06-09): 1M-token context, adaptive-thinking-only, $10/$50 per MTok. Shares weights with limited-access Mythos 5; suspended 2026-06-12 to 07-01 under US export controls after a reported jailbreak.
  • Claude Opus 4.8Anthropic's frontier model for complex agentic coding and enterprise work (API ID claude-opus-4-8, released 2026-05-28): 1M-token context, 128K max output, adaptive thinking only, incremental agentic gains over Claude Opus 4.7.
  • Claude Sonnet 5Anthropic's Sonnet-tier model in the Claude 5 generation (API ID claude-sonnet-5, released 2026-06-30): 1M-token context, 128K max output, adaptive thinking on by default, priced at $2/$10 per MTok introductory, positioned below Claude Opus 4.8 and Claude Fable 5.
  • GLM-5.2Zhipu AI's flagship long-horizon coding/agentic MoE model, distributed via Z.ai (glm-5.2, open weights published 2026-06-17): ~1.05M-token context, MIT-licensed weights, $1.40/$4.40 per Mtok, benchmarked by Zhipu against Claude Opus 4.8 and GPT-5.5 on agentic-coding evals.
  • GPT-5.3-Codex-SparkOpenAI's distilled, low-latency coding model, launched 2026-02-12 as a ChatGPT Pro research preview on Cerebras Wafer-Scale Engine 3 hardware at 1,000+ tok/s. 128K context, text-only, no general API access, and no first-party benchmark score published as of 2026-07-12.
  • GPT-5.5OpenAI's mid-cycle frontier model (API ID gpt-5.5), shipped 2026-04-23 between GPT-5.4 and the GPT-5.6 family: 1.05M-token context, 128K max output, five reasoning-effort levels, positioned for coding and multi-step agentic work.
  • GPT-5.6 LunaOpenAI's fastest, lowest-cost tier of the GPT-5.6 family (released 2026-07-09): 1.05M-token context, 128K max output, $1/$6 per Mtok in/out, but a steep long-context recall cliff versus its Terra and Sol siblings.
  • GPT-5.6 SolOpenAI's flagship in the three-tier GPT-5.6 family (API ID gpt-5.6-sol), GA 2026-07-09: 1.05M-token context, Programmatic Tool Calling, an Ultra subagent mode, and an independently documented reward-hacking rate higher than any prior model METR evaluated.
  • GPT-5.6 TerraOpenAI's balanced mid-tier GPT-5.6 model (API ID gpt-5.6-terra, GA 2026-07-09): 1.05M-token context, $2.50/$15 per-Mtok pricing, pitched as GPT-5.5-competitive at half Sol's price — though independent SWE-bench Pro runs diverge sharply from OpenAI's own figures.
  • Grok 4.5xAI's frontier model (API ID grok-4.5), released 2026-07-08 and co-trained with Cursor on live developer-agent data. 500K context, $2/$6 per Mtok, and a mixed self-reported benchmark record versus Claude and GPT-5.5 rivals; no published system card as of 2026-07-12.
  • Kimi K2.6Moonshot AI's flagship open-weight MoE model (API id kimi-k2.6, GA 2026-04-21): 1T total / 32B active parameters, 262K context, Agent Swarm scaling to 300 parallel sub-agents over 4,000 steps, Modified MIT license.
  • Kimi K2.7-CodeMoonshot AI's open-weight, thinking-only coding model (API ID kimi-k2.7-code, released 2026-06-12): 1T-parameter MoE, 262K context, 32K max output, and vendor-reported gains over Kimi K2.6 on Moonshot's own proprietary agentic-coding suite.

Benchmarks5

  • Humanity's Last ExamClosed-ended benchmark of 2,500 expert-level academic questions across 100+ subjects, built by CAIS and Scale AI to outlive saturated benchmarks like MMLU. Frontier models scored under 10% at launch (January 2025); the top leaderboard score climbed to ~46% by mid-2026.
  • Needle in a HaystackLong-context retrieval test that hides a fact in filler text and sweeps context length against insertion depth. The de-facto acceptance test behind vendor long-context claims — and, per RULER and NoLiMa, a measure of surface retrieval rather than comprehension.
  • OSWorldBenchmark of 369 execution-evaluated computer tasks on Ubuntu — real apps, OS file I/O, multi-app workflows — graded by checking the resulting machine state. Launched 2024 (best agent 12.24% vs 72.36% human); extended by OSWorld-Verified and the long-horizon OSWorld 2.0 suite.
  • SWE-benchBenchmark of AI systems resolving real GitHub issues: given a repository and an issue, produce a patch that passes the repo's own tests. The standard reference for agentic-coding claims — and a case study in scores that conflate model, scaffold, and benchmark contamination.
  • Terminal-BenchBenchmark of AI agents completing real end-to-end tasks in a terminal: each task is a Docker environment with an English instruction, graded by tests on the final container state. A Stanford × Laude Institute project; its leaderboard ranks agent+model pairs, not bare models.

Wanted pages23