fix: add GitHub Copilot model context windows and output limits (#576)

Add context_window and max_output_tokens entries for all models available
through the GitHub Copilot proxy (Claude, GPT, Gemini, Grok), sourced from
https://api.githubcopilot.com/models.

Models are namespaced as "github:copilot:<model>" to avoid collisions with
the same model names served by other providers (which may have different
limits). A new lookupByKey() helper and qualified-key lookup in
lookupByModel() ensures the correct limits are selected when
OPENAI_MODEL=github:copilot.

Without this, Claude models on Copilot would use default context/output
limits that may not match the proxy's actual constraints, causing 400 errors
like "max_tokens is too large".

Related: #515

Co-authored-by: Zartris <14197299+Zartris@users.noreply.github.com>
This commit is contained in:
Zartris
2026-04-10 16:00:26 +02:00
committed by GitHub
parent cb8f8b7ac2
commit a7f5982f64

View File

@@ -12,6 +12,44 @@
*/
const OPENAI_CONTEXT_WINDOWS: Record<string, number> = {
// GitHub Copilot — values from https://api.githubcopilot.com/models (2026-04-09)
// Namespaced so they don't collide with bare model names from other providers.
'github:copilot': 128_000,
// Claude
'github:copilot:claude-sonnet-4': 216_000,
'github:copilot:claude-haiku-4': 200_000,
'github:copilot:claude-sonnet-4.5': 200_000,
'github:copilot:claude-sonnet-4.6': 200_000,
'github:copilot:claude-opus-4': 200_000,
'github:copilot:claude-opus-4.6': 200_000,
// GPT
'github:copilot:gpt-3.5-turbo': 16_384,
'github:copilot:gpt-4': 32_768,
'github:copilot:gpt-4-0125-preview': 128_000,
'github:copilot:gpt-4-o-preview': 128_000,
'github:copilot:gpt-4.1': 128_000,
'github:copilot:gpt-4o': 128_000,
'github:copilot:gpt-4o-2024-08-06': 128_000,
'github:copilot:gpt-4o-2024-11-20': 128_000,
'github:copilot:gpt-4o-mini': 128_000,
'github:copilot:gpt-5-mini': 264_000,
'github:copilot:gpt-5.1': 264_000,
'github:copilot:gpt-5.2': 400_000,
'github:copilot:gpt-5.2-codex': 400_000,
'github:copilot:gpt-5.3-codex': 400_000,
'github:copilot:gpt-5.4': 400_000,
'github:copilot:gpt-5.4-mini': 400_000,
// Gemini
'github:copilot:gemini-2.5-pro': 128_000,
'github:copilot:gemini-3-flash-preview': 128_000,
'github:copilot:gemini-3.1-pro-preview': 200_000,
// Grok
'github:copilot:grok-code-fast-1': 256_000,
// NOTE: bare Claude model names (e.g. 'claude-sonnet-4') are intentionally
// omitted. Different OpenAI-compatible providers may impose different context
// limits for the same model name, so we cannot safely hardcode values here.
// OpenAI
'gpt-5.4': 1_050_000,
'gpt-5.4-mini': 400_000,
@@ -82,6 +120,41 @@ const OPENAI_CONTEXT_WINDOWS: Record<string, number> = {
* Fixes: 400 error "max_tokens is too large" when default 32k exceeds model limit.
*/
const OPENAI_MAX_OUTPUT_TOKENS: Record<string, number> = {
// GitHub Copilot — values from https://api.githubcopilot.com/models (2026-04-09)
'github:copilot': 16_384,
// Claude
'github:copilot:claude-sonnet-4': 16_000,
'github:copilot:claude-haiku-4': 64_000,
'github:copilot:claude-sonnet-4.5': 32_000,
'github:copilot:claude-sonnet-4.6': 32_000,
'github:copilot:claude-opus-4': 32_000,
'github:copilot:claude-opus-4.6': 32_000,
// GPT
'github:copilot:gpt-3.5-turbo': 4_096,
'github:copilot:gpt-4': 4_096,
'github:copilot:gpt-4-0125-preview': 4_096,
'github:copilot:gpt-4-o-preview': 4_096,
'github:copilot:gpt-4.1': 16_384,
'github:copilot:gpt-4o': 4_096,
'github:copilot:gpt-4o-2024-08-06': 16_384,
'github:copilot:gpt-4o-2024-11-20': 16_384,
'github:copilot:gpt-4o-mini': 4_096,
'github:copilot:gpt-5-mini': 64_000,
'github:copilot:gpt-5.1': 64_000,
'github:copilot:gpt-5.2': 128_000,
'github:copilot:gpt-5.2-codex': 128_000,
'github:copilot:gpt-5.3-codex': 128_000,
'github:copilot:gpt-5.4': 128_000,
'github:copilot:gpt-5.4-mini': 128_000,
// Gemini
'github:copilot:gemini-2.5-pro': 64_000,
'github:copilot:gemini-3-flash-preview': 64_000,
'github:copilot:gemini-3.1-pro-preview': 64_000,
// Grok
'github:copilot:grok-code-fast-1': 64_000,
// NOTE: bare Claude model names omitted — see context windows comment above.
// OpenAI
'gpt-5.4': 128_000,
'gpt-5.4-mini': 128_000,
@@ -145,6 +218,19 @@ const OPENAI_MAX_OUTPUT_TOKENS: Record<string, number> = {
}
function lookupByModel<T>(table: Record<string, T>, model: string): T | undefined {
// Try provider-qualified key first: "{OPENAI_MODEL}:{model}" so that
// e.g. "github:copilot:claude-haiku-4.5" can have different limits than
// a bare "claude-haiku-4.5" served by another provider.
const providerModel = process.env.OPENAI_MODEL?.trim()
if (providerModel && providerModel !== model) {
const qualified = `${providerModel}:${model}`
const qualifiedResult = lookupByKey(table, qualified)
if (qualifiedResult !== undefined) return qualifiedResult
}
return lookupByKey(table, model)
}
function lookupByKey<T>(table: Record<string, T>, model: string): T | undefined {
if (table[model] !== undefined) return table[model]
// Sort keys by length descending so the most specific prefix wins.
// Without this, 'gpt-4-turbo-preview' could match 'gpt-4' (8k) instead