Can OpenCode Replace Claude Code? The Real Cost Behind Open Source, a Free Agent, and Picking Your Own Model

The software is free. The model is not.

OpenCode is a coding agent for the terminal, an IDE, and the desktop. The repo anomalyco/opencode is MIT. MIT means you can use, modify, and redistribute the software at no license fee. It does not mean model calls are $0. Claude Code has no separate software price. claude.com/pricing says the free plan can chat, and Claude Code comes with paid plans. Pro is $20 a month, or $200 up front, which they list as $17 a month.

“Can it replace Claude Code?” is two questions. As a client, OpenCode can point at your own models and take the place of the Claude Code program. As a model bill, Go at $10 a month lists Claude Haiku 5.5 and does not list Sonnet, Opus, or Fable. Staying on those three means API prices, not the $10.

Prices were read on 19 October 2026 from the Go docs, the Zen docs, claude.com/pricing, and the Anthropic model prices. The monthly figures multiply those rates by a stated token mix. That is arithmetic, not an export from a kvmboot account or any other account.

Three ways OpenCode charges for models

The software stays at $0. Models have three paths, and they can sit side by side. Claude’s monthly plans are on the same table so the free client is not compared with a missing row.

Go and Go Plus use the same token prices. Plus raises each model’s monthly dollar cap. The Go docs say only one member per workspace can subscribe to Go or Go Plus. Zen docs charges per request from prepaid credit and says it sells at cost, passing card fees through at 4.4% plus $0.30 per transaction. The published example is a $20 credit with a $1.23 card fee, which matches a fee on the amount charged: landing $20 of credit costs about $21.23. Below $5 the balance auto-reloads $20. You can change the amount or turn it off.

A monthly limit stops usage. It does not stop an auto-reload you left on. Usage halts at the limit, and a balance under $5 can still trigger another charge.

• If you attach your own OpenAI or Anthropic key inside Zen, that provider bills the tokens, not Zen. See the Zen docs.
• You can skip Zen. OpenCode connects to other providers directly, and the license fee is still $0. A local or self-hosted model needs its own provider. Power and hardware are not on this table.
• Limited-time free models are not permanent. The privacy notes say some free endpoints may use sessions to improve the model. NVIDIA’s trial endpoints say not to send personal or confidential data. Read that section before pointing a customer repo at “free.”
• The site, inference, and paid products are covered by the terms effective 15 August 2026, with ANOMALY INNOVATIONS, INC. Open-source software that is not hosted is covered only by the repository license.

One stated workload, four different bills

The month is 20 million input tokens and 2 million output tokens. Eighty percent of input is priced as cache reads and 20 percent as base input: 4 million base input plus 16 million cache reads. Cache writes are not in the table. The first write is extra. Prompts stay in the short tier, Haiku at or under 100,000 tokens. This is arithmetic.

Sonnet 5.5 does not match on one cell that day. The Anthropic model prices list cache hits at $0.10 per million, 0.05× the input price. The Zen docs list the same cell at $0.20. Input at $2 and output at $10 match. Opus 5.5 cache reads are $0.20 on both, and Fable 5.1 is $0.25 on both. Use the cache column of the list that actually bills you. “At cost” does not mean every cell already matches Anthropic’s latest cache discount.

If Zen auto-reload runs in $20 steps, the card fee is per charge, not per token. The $32.95 figure is only “one charge that buys exactly $31.20 of credit.”

Ten dollars buys a monthly cap, not ten dollars of credit

Go caps are per model, in dollars. For each model the five-hour window is 20 percent of the monthly cap, the week is 50 percent, and the month is 100 percent. Haiku does not spend Kimi’s cap. A paid Claude plan is the other shape: chat and Claude Code draw one pool, and Anthropic does not publish that pool as a token count.

The rows below are only the ones this bill uses, read from the Go docs on 19 October 2026. Token prices are the same on both plans.

• The Haiku 5.5 mix counts about $1.56. That fits the $15 month and the $3 five-hour window. The subscription is still $10. A quiet month does not turn the $10 into $0.
• The same mix on Kimi K3 counts about $46.80, over the $15 month and over the $3 five-hour window. Go stops at the cap. It does not invoice $46.80. The docs estimate about 110 requests per five hours and 490 per month on Go. That estimate is OpenCode’s, not a count we ran.
• DeepSeek V4 Pro on Go off-peak is $0.66 input, $1.98 output, and $0.022 cache read. Zen lists the same name at $1.74 / $3.48 / $0.145. Go’s docs put peak at 01:00–04:00 and 06:00–10:00 UTC on weekdays. Other hours, including weekends, are off-peak.
• On a light month the subscription costs more than the meter. One pass of GLM-5.3 Flash is about $2.08, so Zen stays near that number. At 10×, $20.80 is still under Go’s $60 cap, and Go’s $10 is the lower bill.

What the Claude monthly fee buys, and what it does not

Pro includes Claude Code and shares a five-hour session limit and a weekly limit with chat on the web, desktop, and phone. At the limit you wait for the reset, or you switch to API credit billed on the Anthropic model prices. The Pro / Max help says an ANTHROPIC_API_KEY in the environment makes Claude Code use that key, so the bill becomes API usage instead of the plan. To stay on the plan, sign in with the subscription only and decline the API-credit prompt.

Max starts at $100 a month, at 5× or 20× Pro usage. The API credit rules say Max 5× includes $100 of API credit a month and the 20× tier includes $200. The Team plan help says a standard seat is $25 a month or $20 annualized, about 1.25× Pro per session, with $20 of API credit per seat. Premium is $125 a month or $100 annualized, about 6.25× Pro, with $100 of API credit per seat. Team credits pool across seats, cap at $500, and expire at the end of the cycle. They do not roll over.

Those credits cover the Claude API, Managed Agents, the Agent SDK, and the playground. The same page says they do not cover interactive Claude Code or extra usage in the apps. If you are already on Max or Team and point OpenCode at your own Anthropic key, that key is the Claude API. On this table it falls inside the credit. Interactive Claude Code does not. We did not reconcile a Console invoice for you. Anthropic’s record is the one that counts.

• Pro’s $20 is not “equal to $29.60 of Sonnet.” Anthropic does not publish the plan as a token count. When the allowance covers the month, the plan price is the ceiling. When it does not, the overflow returns to API rates.
• The Fable mix is $144.00. Max is listed from $100. Which one is lower depends on whether the plan allowance covers these 20 million input tokens and 2 million output tokens, not on which sticker is smaller.
• The API credit bundled with Max and Team does not pay for extra interactive Claude Code. More Claude Code after the cap is a separate usage-credit path, billed at API rates.
• Go is not sold as a team seat. One member per workspace can subscribe. Claude Team is per seat, with a two-seat minimum.

Choose from the bill you already pay

OpenCode can replace the agent software. It does not replace the Sonnet, Opus, or Fable allowance inside a paid Claude plan. Staying on those three sends you back to the API list, plus whatever gateway fee you picked.

• Some months you barely code: do not subscribe to Go. The software is $0. Pro still bills $20, or the annual charge, if you keep it.
• Easy edits go to Haiku, Flash, or DeepSeek, and hard diffs go to Sonnet: OpenCode is built for that switch. Claude Code stays on Claude models.
• Counted usage on a Go model sits steadily between $10 and that model’s cap, as with GLM-5.3 Flash at 10× above: Go at $10 is below Zen’s meter. If you regularly hit a $15 cap such as Kimi K3, you bought an early stop, not unlimited Kimi.
• The work is Claude models inside a plan, and the allowance usually holds: stay on Claude Code. Moving the same tier to Zen to be “open source” saves $0 of software and puts the model back on the list price.

This piece does not say who writes the better patch. Without a shared coding log, open source is not “stronger” or “cheaper.” The Claude plan tiers are in Claude Code 2026 pricing and plans. If the model goes through another gateway, the per-million arithmetic is inOpenRouter’s price per million tokens.

FAQ

Does OpenCode itself cost money?

The software does not. The repo is MIT. You pay for the model: Go at $10 or $40 a month, Zen metered plus the card fee, or your own provider key.

Can Go’s $10 run Claude Opus?

No. On the Go list read 19 October 2026, the only Claude model is Haiku 5.5, with a $15 monthly cap. Opus, Sonnet, and Fable are on Zen or on your own Anthropic key, at list prices.

Are Zen’s free models free forever?

The docs say limited time. Some free endpoints may use data to improve the model, and the NVIDIA trial endpoints say not to send confidential data. Free is for trying a model, not for turning a customer repo’s bill into $0.

Can Max API credit run Claude Code?

Anthropic says no. The credit does not cover interactive Claude Code. It covers the Claude API. OpenCode on your own Anthropic key is the API path, not the Claude Code product.

I already pay for Claude Pro. Should I switch clients?

If the allowance holds and you only need Claude models, the bill gives you no reason. Look at OpenCode when you want a cheaper model in the same week, or when a whole idle month should not cost $20.