Repository navigation
Copilot provider: 400 model_not_supported for claude-haiku-5-5 / claude-sonnet-5-5 (stale COPILOT_MODEL_ID_MAPPING) #1022
Description
Summary
Selecting Claude Haiku 5.5 (or Claude Sonnet 5.5) under the GitHub Copilot provider in /model fails on every turn with:
Error: 400 Invalid_request_error The requested model is not supported.
The very same model works fine under the Command Code provider. So it is a Copilot-provider-only failure and does not depend on the user's plan or config.
Root cause
@byokkit/cmd-provider-copilot@0.1.2 (latest) — COPILOT_MODEL_ID_MAPPING in dist/chunk-EO2W2NPS.js maps Command Code hyphenated ids → Copilot dotted ids. That is the intended mechanism (per the comment right above the table: "these now map hyphen→dot like the older Claude ids"), but the table is stale — it is missing the newest Claude 5.5 ids.
toCopilotModelId() falls through (?? modelId), forwards the hyphenated id verbatim, and Copilot rejects it.
var COPILOT_MODEL_ID_MAPPING = {
"claude-fable-5-1": "claude-fable-5.1",
"claude-opus-5-5": "claude-opus-5.5", // present → works
"claude-sonnet-4-6":"claude-sonnet-4.6",
"claude-opus-4-8": "claude-opus-4.8",
"claude-opus-4-7": "claude-opus-4.7",
"claude-opus-4-6": "claude-opus-4.6",
"claude-haiku-4-5-20251001": "claude-haiku-4.5"
// missing:
// "claude-haiku-5-5": "claude-haiku-5.5"
// "claude-sonnet-5-5": "claude-sonnet-5.5"
};Proof (direct Copilot API, provider's own headers)
POST https://api.githubcopilot.com/chat/completions, Copilot-Integration-Id: vscode-chat:
| model id sent | result |
|---|---|
claude-haiku-5-5 |
400 {"message":"The requested model is not supported.","code":"model_not_supported","type":"invalid_request_error"} |
claude-haiku-5.5 |
200 |
claude-sonnet-5-5 |
400 |
claude-sonnet-5.5 |
200 |
claude-opus-5-5 |
200 (present in the table → works) |
Copilot's own /models list advertises claude-haiku-5.5, claude-sonnet-5.5, claude-opus-5.5 (dotted), confirming the target id form.
Expected
Claude Haiku 5.5 / Sonnet 5.5 work under the GitHub Copilot provider exactly like they do under the Command Code provider.
Fix
Extend COPILOT_MODEL_ID_MAPPING with the missing 5.5 entries:
"claude-fable-5-1": "claude-fable-5.1",
"claude-opus-5-5": "claude-opus-5.5",
+ "claude-sonnet-5-5": "claude-sonnet-5.5",
+ "claude-haiku-5-5": "claude-haiku-5.5",Environment
- Command Code CLI v1.82.1 (latest)
@byokkit/cmd-provider-copilot@0.1.2(latest; no newer version published)- macOS arm64 · zsh
- Trace IDs:
42684743eb4a6478f6dbef94e0990651,51fdad26433974c045ae0e67a301dac1,d9795050afa64495e9a96fd6a51772f2
Related but separate: #738 (GPT-lane summaryParts crash on Copilot's Responses API).
Activity
web3wannabe commentedon Oct 14, 2026
Proposed fix (verified)
File:
@byokkit/cmd-provider-copilot@0.1.2→dist/chunk-EO2W2NPS.js→COPILOT_MODEL_ID_MAPPINGAdd the two missing hyphen→dot entries:
Why this works:
toCopilotModelId()isMAPPING[id] ?? id, so with these entries the provider emits the exact dotted id Copilot accepts instead of forwarding the hyphenated one verbatim.Verified after applying the patch to the installed package:
and a direct
POST https://api.githubcopilot.com/chat/completionswith those dotted ids returns200(the hyphenated ids return the400 model_not_supportedshown in the report).