Use Kimi K3 in OpenCode: Setup and Workflow Guide

OpenCode provides the agent interface, repository tools, approval flow, and terminal experience. Kimi K3 provides model inference. The two products are separate, so installing OpenCode does not automatically create a Kimi account or include model usage. You need an eligible Kimi service, a valid credential, the correct base URL, and a supported model identifier. The official setup currently documents Kimi K3 as an available model for OpenCode.

This separation is useful when troubleshooting. Authentication errors usually belong to the provider configuration. Missing files or failed shell actions usually belong to the agent permissions or working directory. Weak answers may come from prompt context, model selection, or reasoning configuration. Treating the stack as distinct layers makes problems easier to isolate than reinstalling everything after a single error.

Install OpenCode through its current official instructions and run it inside a version-controlled project. Confirm that the project builds before introducing an agent. Save or commit existing work, review ignore rules, and ensure secrets are not stored in files the agent will read. Define the commands used for linting, type checking, tests, and builds so verification is repeatable.

Start with conservative tool permissions. Read and search operations can be low risk, while edits, package installation, shell execution, network calls, and deletion deserve review. A disposable branch or isolated worktree is appropriate for the first session. An agent that can modify a repository is useful precisely because it can act; the approval model should match the consequences of those actions.

Create the appropriate API credential in the Kimi service you intend to use. Store it using OpenCode’s supported provider configuration rather than pasting it into prompts, source files, or committed environment examples. Select the documented base URL and Kimi K3 model identifier for that service. Official Kimi Code and Kimi Platform endpoints may use different account products and usage rules, so do not mix values from separate guides.

If the client exposes a context-window setting, confirm it matches the capacity you actually intend to use. Official documentation notes that some third-party tools default below K3’s maximum, so the full window may require an explicit value. Configure reasoning effort only with supported names. Unknown effort values can produce request errors rather than silently falling back.

The first task should prove each layer without risking a broad edit. Ask OpenCode to identify the project language, package manager, entry point, and test command, then request a concise repository map. Confirm that the files it cites exist and that no write occurred. This tests authentication, model selection, repository access, and response streaming with a small amount of context.

Next, ask for a plan to fix a minor known issue without editing. Review whether the plan follows local conventions and names the correct validation commands. Only then permit a contained change. Inspect the diff and run the checks yourself or through an approved tool call. A staged validation sequence provides much better diagnostics than starting with a large autonomous refactor.

Give each session one outcome. State acceptance criteria, constraints, relevant files, and what the agent must not change. Ask for exploration before implementation when the repository is unfamiliar. For a risky migration, require reversible stages and a rollback path. For debugging, provide reproduction steps and raw error output instead of a conclusion about the cause.

Long context can keep more repository material available, but search-first workflows are still efficient. Let the agent trace symbols and dependencies, then load the files that matter. Interrupt if it repeats unsuccessful steps or expands scope. At the end, request a summary of changed files, checks run, known limitations, and any manual follow-up. Verify that summary against the actual diff.

A 401 or 403 response usually indicates a missing, invalid, expired, or unauthorized credential. A model-not-found response suggests the wrong identifier, endpoint, region, or plan. A context error means the combined prompt, tools, history, and requested output exceed the configured or provider limit. A reasoning validation error can come from an unsupported effort name. Read the full response before changing configuration.

If authentication succeeds but the agent cannot operate, check the working directory, ignore patterns, tool permissions, shell availability, and project commands. If usage is unexpectedly high, inspect context size, repeated tool output, retries, and cache behavior. Record the OpenCode version and the official guide version because integration details can change. Avoid copying old configuration snippets without verifying them against current documentation.