Companion page Updated quarterly AI Agents for Everyone
The book is ink on paper — or pixels on a Kindle screen — and once it's printed it stays still. The field doesn't. This is where the model lineup, indicative pricing, MCP ecosystem and any errata get refreshed without reprinting the book. Public page — no login, no gate.
Edition April 2026 Last verified 26 April 2026
Old Forge · Field Manuals
AI Agents
for everyone.
From ChatGPT to autonomous
systems that actually work
Buy the book
The book references this page in the Introduction, the Pace and Evolution section, every pricing-table footnote, and the Resource Directory.
Names rotate every few months; the tiers are stable. The book argues you should pick a tier first — based on the work the agent has to do — and only then pick a specific model. The names below are accurate as of April 2026; verify at the provider before relying on any of them in production.
Tier 1 · Frontier-Opus class
Best-in-class reasoning, tool use and long-context coherence. Use when the work genuinely needs it — research agents, multi-step planning, code at the edge of the model's ability.
Tier 2 · Frontier-Sonnet class
The default choice for most production agentic work. Strong reasoning, fast enough for interactive use, dramatically cheaper than Tier 1.
Tier 3 · Mid
For the boring half of your pipeline — intent classification, routing, summary drafts, retrieval re-ranking. Cheap enough to run at volume; capable enough to do the work well.
Tier 4 · Small / on-device
Embedding, simple extraction, edge inference. Pennies per million tokens, or free if you're running open weights on your own kit.
Names verified at provider sites before publication of this update. Anthropic, OpenAI, Google and Mistral all rotate model names within a tier without warning; treat this list as a starting point, not a contract.
Bands, not point values, because providers move pricing every few months. Conversions assume £1 ≈ US$1.27. Always check the live provider page below before quoting numbers to a client.
| Tier | Input £ / 1M | Output £ / 1M |
|---|---|---|
| Tier 1 · Frontier-Opus | £8 – £14 | £40 – £100 |
| Tier 2 · Frontier-Sonnet | £1.50 – £3 | £7 – £15 |
| Tier 3 · Mid | £0.20 – £0.80 | £0.80 – £4 |
| Tier 4 · Small / on-device | £0.04 – £0.12 | £0.16 – £0.50 |
Prompt caching, batch APIs and committed-use discounts can move the effective rate significantly below the band on Tier 1 and Tier 2 — see the book's pricing chapter for the conditions under which each one is worth claiming.
Eighteen months ago, 32K tokens was the working ceiling. As of April 2026, every Tier 1 and Tier 2 frontier model offers at least a 200K-token window, with Anthropic and Google offering 1M-token windows on selected SKUs and Gemini still leading at 2M tokens. The practical implication is that whole codebases, full regulatory packs, and the back-history of a customer account now fit in a single call — though the cost of using all of it on every request remains the constraint, not the window itself.
The book's guidance still holds: retrieval beats long context on cost almost every time, but long context lets you stop worrying about chunking on the cases where it doesn't.
Model Context Protocol has gone from a Claude-only experiment to a cross-vendor de facto standard in roughly eighteen months. The book argues integration time has collapsed from weeks to days for mainstream tools — this is the shape of that, today.
Shipping · first-party
In beta or limited · first-party
Community-only · vendor not yet committed
Community servers vary wildly in quality. The book's chapter on MCP explains the questions to ask before relying on one — auth model, rate-limit handling, schema fidelity, who maintains it.
No known errata in the April 2026 edition.
Spotted one? Write to info@oldforge.tech with the page number and the issue. Real corrections will be listed here, with the date they were filed.
AI Agents for Everyone goes live on Amazon UK and Amazon US. This companion page launches with the same April 2026 snapshot of models, pricing, context windows and the MCP ecosystem that the book is calibrated against.
Future quarterly updates (Q3 2026, Q4 2026, Q1 2027 and onwards) will appear above this entry. The commitment is one update per quarter; the cadence may tighten if a vendor announces something that genuinely changes the picture.
About
AI Agents for Everyone sits in the gap between the books that teach engineers to build and the ones that tell executives why AI matters — written for product managers who have to make credible decisions about agentic systems, without drowning in transformer maths or marketing hype. Tone is British, direct, occasionally witty, never patronising. Pricing is in pounds.
The author, Andrei Trâmbiţaş, is the proprietor of Old Forge Technologies, a one-person workshop in Suffolk taking on bespoke software and AI-adoption work for small businesses. Two decades across DHL, Microsoft and Kaseya. MSc in Computer Science with Cyber Security. Published research on decentralised compute for large-language-model inference.