fix: declare a JSON 200 for intern chat so the Python SDK compiles

[devin-ai-integration]

Summary

Every "Generate (spec change merged)" run since the intern chat endpoint landed (openrouter-web#43374, spec update #867) fails in Compile SDK, so no Python release has shipped since 1.1.156 and Decisions is missing from PyPI and the Python docs:

src/openrouter/interns.py:2060: Incompatible return value type (got "EventStream[InternChatCompletionChunk]", expected "InternChatCompletionChunk")

createInternChatCompletion is the only operation in the spec whose 200 declares text/event-stream alone. With sseFlatResponse: true, the Python generator (pinned 1.787.0) annotates chat() as returning the flattened chunk while emitting an EventStream body. TypeScript and Go generate the same operation correctly.

This adds a Python-only overlay that declares an application/json sibling on that 200 pointing at the same InternChatCompletionChunk schema. The generator then produces the supported SSE-overload shape:

def chat(...) -> Union[components.InternChatCompletionChunk, eventstreaming.EventStream[components.InternChatCompletionChunk]]

Runtime behaviour is unchanged (stream=True is required, the server always streams). The public spec stays SSE-only, so the TS and Go SDKs are untouched. Supersedes openrouter-web#44455, which made the same change in the public spec and would have widened the TS return type.

Tried and rejected: x-speakeasy-sse-overload: false on the operation and inferSSEOverload: false in gen.yaml both leave the error in place with 1.787.0, so the trigger is the flat SSE response path, not overload inference.

Note: merging this does not trigger generation on its own (that workflow filters on in.openapi.yaml). The nightly Generate run or a manual workflow_dispatch will produce the release PR.

Verification

speakeasy run -t open-router --skip-versioning with the pinned 1.787.0 on this branch: generation succeeds, mypy src/openrouter and pyright src/openrouter report no issues (902 files). Same command on main reproduces the CI error.

Searched existing PRs: none address this.

Link to Devin session: https://openrouter.devinenterprise.com/sessions/3f706d7e7e6f4a1dbe42eef374519a68
Open in Devin Desktop: https://openrouter.devinenterprise.com/desktop/session/3f706d7e7e6f4a1dbe42eef374519a68?variant=devin
Requested by: @christineschen

[devin-ai-integration]

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---

Original prompt from Christine

SYSTEM:
<latest_message>
Christine Chen (U0B8QM7RKLL) [ts=1789686258.156009]: @Devin look into why ts and python sdks aren't enabled
</latest_message>

=== BEGIN THREAD HISTORY (in #proj-jev) ===
Abhinav Pola (U090K0G7JF3) [ts=1789682735.294299]: LETSSS GOOO
&gt; Real request works. typesafe/jev-1.13 → HTTP 200, provider TypeSafe, one noul answer (0.97), usage 289 in / 21 out, cost 0.000012138 (exactly 289 × 4.2e-8, so pricing is live). Same result for the dated permaslug.

Jacky Liang (U0AUY9BQV18) [ts=1789682862.355109]: this is on openrouter yeah?

Abhinav Pola (U090K0G7JF3) [ts=1789682867.572409]: yup

Abhinav Pola (U090K0G7JF3) [ts=1789682874.528679]: private endpoint (only our org can use it)

Ayush Patel (U0B8L6RNMA9) [ts=1789683251.473799]: aside i wonder why they opted for that model naming, i hope they dont just release a shit ton of minor versions

they do jev-latest in their docs maybe to point people to not use jev-1.13 specifically

ATTACHMENT:"https://openrouter.devinenterprise.com/attachments/f9f4910c-8f9f-44d9-af01-1e4b663826f9/image.png"

Louis Vichy (U0ACWETHNLT) [ts=1789683500.173969]: @Abhinav Pola btw what's the SDK looking like?

Louis Vichy (U0ACWETHNLT) [ts=1789683518.815939]: do we have the SDK gen for alpha API hooked up or is that... a separate hurdle

Abhinav Pola (U090K0G7JF3) [ts=1789683698.072549]: just saw this <https://openrouter.ai/docs/client-sdks/go/sdks/decisions/README`#`decisions>

Louis Vichy (U0ACWETHNLT) [ts=1789685494.257079]: Weird, so go works, but TS and Python isn't?..

Abhinav Pola (U090K0G7JF3) [ts=1789685510.082919]: i'm not sure what went wrong

Abhinav Pola (U090K0G7JF3) [ts=1789685522.539739]: docs arent showing up either

Louis Vichy (U0ACWETHNLT) [ts=1789685523.518409]: cc @Christine Chen do you know why the TS and Python are not being enabled

Christine Chen (U0B8QM7RKLL) [ts=1789686242.551129]: hmm I'm not sure, t... (742 chars truncated...)