copilot-byok

name	copilot-byok
description	Configure and switch between BYOK (Bring Your Own Key) LLM providers for both GitHub Copilot CLI and VS Code Chat. Use when setting up OpenAI, Azure OpenAI, Anthropic, Ollama, Moonshot, OpenCode Go, OpenRouter, or other OpenAI-compatible endpoints; creating or switching reusable provider profiles for CLI; switching between multiple accounts (API keys) for the same provider; configuring chatLanguageModels.json for VS Code; calculating max prompt or output token overrides; configuring wire API and reasoning effort; or troubleshooting COPILOT_PROVIDER_BASE_URL, COPILOT_PROVIDER_TYPE, COPILOT_PROVIDER_API_KEY, COPILOT_MODEL, COPILOT_PROVIDER_WIRE_API, COPILOT_PROVIDER_MAX_PROMPT_TOKENS, COPILOT_PROVIDER_MAX_OUTPUT_TOKENS, COPILOT_OFFLINE, and VS Code language model settings.
metadata	{"author":"arisng","version":"0.16.0","lastVerified":"2026-08-09T00:00:00.000Z"}

Copilot BYOK Provider Configuration

Use this skill to configure BYOK (Bring Your Own Key) LLM providers for both GitHub Copilot CLI and VS Code Chat. Manage repeatable CLI provider profiles and VS Code chatLanguageModels.json from a single source of truth.

Follow this workflow

1. Determine the provider (OpenCode Go, OpenRouter, …) and the harness (Copilot CLI or VS Code Chat) the user needs.
2. Read the reference file that matches the current need:
   • Provider-specific content is grouped by LLM provider under references/provider/<provider>/ (each provider has harness-specific files).
   • Universal/shared mechanisms (env vars, API-key storage, VS Code file rules, reasoning-effort lookup, CLI account switching) live under references/shared/.
3. For CLI, prefer scripts/byok-profile.ps1 for repeated use or quick switching between providers.
4. For VS Code, use the Chat: Manage Language Models UI command (see the provider's vs-code.md).
5. Keep secrets out of files. Prefer ${ENV_VAR} placeholders and user-scoped environment variables.

Choose the path

Provider + harness matrix

Read the provider file first, then the harness file:

Provider	Copilot CLI	VS Code Chat
OpenCode Go	references/provider/opencode-go/cli.md	references/provider/opencode-go/vs-code.md
OpenRouter	references/provider/openrouter/cli.md	references/provider/openrouter/vs-code.md

Shared references (any provider, any harness)

• Env-var semantics / provider types / wire-format rules: references/shared/environment-variables.md — read for manual one-off CLI setup or token-limit sizing.
• API key storage or rotation: references/shared/api-key-storage.md.
• chatLanguageModels.json mechanism (secret storage, per-agent model pinning, quick start, troubleshooting): references/shared/chat-language-models-json.md — read for VS Code BYOK setup.
• Reasoning-level configuration: read the grounded per-model lookup references/shared/reasoning-effort-lookup.md, then apply --reasoning-effort per invocation. Cross-surface mapping (CLI flag ↔ env var ↔ SDK API ↔ VS Code) lives in the copilot-cli-subsession skill's copilot-sdk-parity-matrix.md.
• Multiple accounts for one provider (CLI): references/shared/copilot-cli-accounts.md.

VS Code uses chatLanguageModels.json and ignores COPILOT_PROVIDER_* env vars.

Other scenarios

• New provider not yet documented: create references/provider/<provider>/ with cli.md + vs-code.md (mirroring opencode-go/), reuse references/shared/*, and register it in the matrix above. Keep the provider's model/reasoning-effort rows in the provider file, not in shared/reasoning-effort-lookup.md.

Use the profile manager first

Use scripts/byok-profile.ps1 when the user wants repeatable setup, named profiles, or quick switching.

Run the following commands from the installed copilot-byok skill folder (the folder that contains this SKILL.md).

Common commands:

# List profiles
.\scripts\byok-profile.ps1 list

# Add a profile interactively
.\scripts\byok-profile.ps1 add

# Inspect a stored profile
.\scripts\byok-profile.ps1 show openai

# Run Copilot CLI with a profile for one session
.\scripts\byok-profile.ps1 run ollama

# Apply a profile to the current shell
. .\scripts\byok-profile.ps1 set-env openai

Pass extra Copilot CLI arguments through run (do not pass --model; model is sourced from the profile):

.\scripts\byok-profile.ps1 run openai --help

Profiles are stored in ~/.copilot/byok-profiles.json or $env:COPILOT_HOME\byok-profiles.json.

Switch between multiple provider accounts

When you have multiple subscriptions for the same provider (for example, two OpenCode Zen accounts with separate API keys), register the accounts once and switch per session — no profile edits needed.

1. Register accounts in ~/.copilot/byok-profiles.json

{
  "accounts": {
    "opencode-home": { "keyEnv": "OPENCODE_API_KEY_HOME", "label": "OpenCode Zen (Home)" },
    "opencode-work": { "keyEnv": "OPENCODE_API_KEY_WORK", "label": "OpenCode Zen (Work)" }
  },
  "activeAccount": "opencode-home"
}

keyEnv holds the name of an environment variable with that account's key — never the raw key. activeAccount sets the default.

2. Opt profiles in with accountGroup

Add "accountGroup": "opencode" to each profile that should use the registry (the add wizard sets it automatically for the OpenCode Go preset). Profiles without accountGroup never participate.

3. Manage and switch accounts

.\scripts\byok-profile.ps1 accounts
.\scripts\byok-profile.ps1 use opencode-work
.\scripts\byok-profile.ps1 run opencode-go-deepseek-v4-flash
.\scripts\byok-profile.ps1 run opencode-go-deepseek-v4-flash --account opencode-work

Resolution order: --account flag → profile account pin → activeAccount. If nothing resolves, the profile falls back to its legacy apiKey with a warning. For sub-sessions, pass -ByokAccount opencode-work to Invoke-CopilotCliSubSession.ps1.

4. Add the second account in VS Code Chat

VS Code ignores the CLI accounts registry — each account is a separate provider entry with its own key in secret storage. To add the second account:

1. Chat: Manage Language Models → Add Models → Custom Endpoint, name it OpenCode Go (Work, OpenAI), paste the work key, API Type Chat Completions. This stores the key and writes a ${input:chat.lm.secret.*} reference.
2. Run the helper from the skill's scripts/ folder — it renames the existing OpenCode Go (OpenAI|Responses|Anthropic) providers to (Home, …) and clones them as (Work, …) using the new secret reference:

.\scripts\opencode-vscode-add-work-account.ps1

3. Reload the window (Developer: Reload Window); both accounts appear in the model picker.

See references/provider/opencode-go/vs-code.md for the full manual table when you need more than two accounts, and references/shared/copilot-cli-accounts.md for the CLI registry semantics.

Reference index

References are grouped by provider (under references/provider/) and by universal/shared aspects (under references/shared/).

• references/provider/opencode-go/cli.md
  • Read when configuring OpenCode Go for Copilot CLI: prerequisites and keys, base URL + endpoint per family, available-models table with reasoning-effort support, manual env-var examples, GPT-5.6 Luna wire-format matrix + grounded token overrides, profile-based setup.
• references/provider/opencode-go/vs-code.md
  • Read when configuring OpenCode Go for VS Code Chat (chatLanguageModels.json): full provider JSON per model family (chat-completions / responses / messages), multiple OpenCode Zen accounts (Home/Work) incl. the opencode-vscode-add-work-account.ps1 helper.
• references/provider/openrouter/cli.md
  • Read when configuring OpenRouter for Copilot CLI. Covers environment variables, :floor / :nitro routing suffixes, CLI profile, manual env-var setup, and the empirical per-model audit.
• references/provider/openrouter/vs-code.md
  • Read when configuring OpenRouter for VS Code Chat (chatLanguageModels.json). Covers the UI quick-add path and the ready-to-use provider JSON.
• references/provider/openrouter/README.md
  • OpenRouter provider index: harness router + key provider facts.
• references/shared/environment-variables.md
  • Read when you need CLI env-var semantics, provider types, wire-format rules, model requirements, token-override calculation, or offline-mode notes (any provider).
• references/shared/api-key-storage.md
  • Read when the user needs secure key storage, persistent Windows environment variables, key rotation, or ${ENV_VAR} placeholder guidance.
• references/shared/chat-language-models-json.md
  • Read when the user wants to configure BYOK models in VS Code Chat. Covers the config file, secret storage, shared model-configuration rules, per-agent model pinning via .agent.md frontmatter, agent-specific model settings, quick start, and troubleshooting.
• references/shared/reasoning-effort-lookup.md
  • Read when you need the per-model --reasoning-effort support lookup and verification workflow (the authoritative source that copilot-cli-subsession defers to).
• references/shared/copilot-cli-accounts.md
  • Read when the user holds multiple accounts for the same provider (CLI registry, accounts/use/--account, resolution order).
• references/provider/opencode-go/README.md
  • Provider index: harness router + key provider facts + usage limits.

Apply these operating rules

• Prefer ${ENV_VAR} placeholders over raw API keys in JSON.
• Treat openai as the default provider type for OpenAI-compatible endpoints such as Ollama, vLLM, Foundry Local, and Moonshot.
• Set COPILOT_PROVIDER_TYPE=azure only for Azure OpenAI and anthropic only for Anthropic.
• OpenCode Go serves all models from the single base URL https://opencode.ai/zen/go/v1. Live probe (2026-08-03, CLI 1.0.77): DeepSeek, GLM, Kimi, MiMo, Qwen3.x and MiniMax all work via COPILOT_PROVIDER_TYPE=openai (chat/completions) — the anthropic path is not required. gpt-5.6-luna also responds via chat/completions, so the documented "Responses-API only" constraint no longer holds for this gateway (both wire formats work). Store the personal OpenCode key as OPENCODE_API_KEY_HOME and the work key as OPENCODE_API_KEY_WORK — both at User scope (never Machine scope).
• CRITICAL: COPILOT_MODEL must use the bare model ID (e.g., deepseek-v4-flash), not the opencode-go/ prefix. The prefix is only used in OpenCode TUI config and in Copilot CLI profile names — never in COPILOT_MODEL.
• For GPT-5 class OpenAI models, prefer COPILOT_PROVIDER_WIRE_API=responses. On OpenCode Go both completions and responses work for gpt-5.6-luna (probe 2026-08-03); responses remains the recommended default for GPT-5-class.
• Use COPILOT_OFFLINE=true only when the user explicitly wants Copilot CLI isolated from GitHub services; note that full isolation still depends on the provider endpoint being local or private.
• If the model is not in Copilot CLI's built-in catalog, set explicit prompt and output token overrides instead of assuming Copilot will infer them correctly.
• Profile proxyPort field: For Kimi models from https://api.moonshot.ai (which require top_p=0.95), add "proxyPort": 443 to the profile and the run command will auto-start the local proxy and route through https://moonshot.local/v1. The proxy strips top_p to 0.95 before forwarding to Moonshot.

Configure reasoning effort correctly

Use Copilot CLI's --reasoning-effort option for model reasoning level control. The authoritative per-model lookup — which levels a specific model supports and the recommended default — is references/shared/reasoning-effort-lookup.md (OpenCode Go focus; method applies to any BYOK model).

• Supported levels: none, minimal, low, medium, high, xhigh, max (per-model subset may vary — e.g., DeepSeek V4 models on OpenCode Go only support low, medium, high; minimal is newer, verified in CLI 1.0.77).
• Apply it per run, for example:

.\scripts\byok-profile.ps1 run dprocess-openai-gpt-54 --reasoning-effort medium

For OpenAI models, you may also enable summaries:

.\scripts\byok-profile.ps1 run dprocess-openai-gpt-54 --reasoning-effort high --enable-reasoning-summaries

Model compatibility warning

Not all models support Copilot CLI's --reasoning-effort levels. If you get:

Model "glm-5.2" does not support reasoning effort configuration (requested: "high").

it means the model's API does not expose controllable reasoning effort levels. Known families without reasoning-effort support:

• GLM (glm-5, glm-5.1, glm-5.2) — Zhipu AI / OpenCode Go (no controllable levels)
• GLM-5.3-Flash (glm-5.3-flash) — Zhipu AI / OpenCode Go (thinking always-on, defaults to max; model supports low/high/max but gateway may not expose)
• MiMo (mimo-v2.5, mimo-v2.5-pro, mimo-v2-pro, mimo-v2-omni) — Xiaomi / OpenCode Go
• Kimi K2.x (kimi-k2.7-code, kimi-k2.6, kimi-k2.5) — Moonshot AI / OpenCode Go (thinking is implicit / always-on)
• Qwen3.x (qwen3.7-plus, qwen3.7-max, qwen3.6-plus, qwen3.5-plus) — Alibaba / OpenCode Go (implicit thinking; anthropic type per OpenCode Go docs)
• Qwen3.8-Flash (qwen3.8-flash) — Alibaba / OpenCode Go (anthropic type; may support reasoning effort low/medium/high/xhigh — verify on gateway)
• MiniMax (minimax-m3, minimax-m2.7, minimax-m2.5) — MiniMax / OpenCode Go (implicit thinking; openai type per 2026-08-03 probe)

When using these models, omit --reasoning-effort entirely. The model will use its built-in default reasoning behavior.

To check whether a model supports it, try --reasoning-effort none (the least demanding level). If that also fails, the model simply doesn't support the feature.

The profile system tracks this per model. Profiles for models that do not support reasoning effort set "reasoningEffortSupported": false. The run command detects incompatible --reasoning-effort/--effort arguments, strips them before forwarding to Copilot CLI, and displays a clear notice. This prevents the API error. Support is derived from the shared no-support model list when the profile flag is absent (hand-added profiles), so run/set-env/show and Invoke-CopilotCliSubSession.ps1 stay consistent.

Do not claim a dedicated COPILOT_* environment variable exists for reasoning effort unless copilot help environment in the user's installed CLI version explicitly lists one.

Grounding and evidence standard

When answering questions in this domain, always separate grounded facts from inference:

1. Cite authoritative evidence used (for example, copilot --help, copilot help environment, provider model docs).
2. State what is directly evidenced versus inferred operational guidance.
3. End with an explicit conclusion:

• Grounding status: evidence-backed when all key claims are directly supported.
• Grounding status: mixed (evidence + inference) when any recommendation is inferred.

Do not present inferred workarounds (for example wrapper aliases for sticky defaults) as first-class documented product features.

Calculate token overrides conservatively