[michaelwang11394]

What changed

hyperframes capture captions images with Vertex AI. It reads the region (HYPERFRAMES_VERTEX_LOCATION) and the model id from the environment, which can come from a project's .env file. The Google SDK builds the request host from the region and the request path from the model id.

• The region must be a plain Google Cloud location name: lowercase letters, digits and hyphens. This covers every regional location (for example us-central1, europe-west4, me-central2), the us and eu multi-regions, and global. A region can no longer contain a ., /, @, : or #, so the request host always stays on googleapis.com.
• The model id must be one or more /-separated segments. Each segment starts with a letter or digit and contains only letters, digits, _, ., -, @ and :. This rejects % (which can encode ..), ?, #, a leading / and empty segments. A colon is allowed inside a segment because Vertex endpoint paths in domain-scoped projects contain one (projects/example.com:proj/...); it cannot change the request host.
• If either check fails, captioning is skipped with a warning before a Google client is created, so no token is fetched and no request is sent.

Every real region and Google model id behaves exactly as before, including the defaults (us-central1, gemini-2.5-flash, gemini-3.1-flash-lite-preview). OpenRouter model ids are not checked, because they go in the request body rather than the URL.

Not done

• hyperframes snapshot --describe also reads HYPERFRAMES_GEMINI_MODEL, and it is not checked here. That path uses a Gemini API key on a fixed host, and the SDK already rejects .., ? and & in model ids.
• HYPERFRAMES_VERTEX_PROJECT_ID also goes into the request path and is not checked. It cannot change the request host.

Testing

• New cases in packages/cli/src/capture/contentExtractor.test.ts: 10 rejection cases (5 regions, 5 model ids) that fail without the fix, plus accepted regions (global, us, eu, europe-west4) and accepted model ids (a bare id, publisher/model, a Model Garden id with @version, and a domain-scoped endpoint path). All 46 tests in the file pass.
• Lint, format, comment ratchet, fallow and typecheck hooks pass.
• Not run against a live Vertex project. Not run on Windows (no platform-specific code).

🤖 Generated with Claude Code

[heygengenesis]

Verdict: APPROVE · 0 blocker · 0 important · 0 nits · head 9bca2d9

I checked this against @google/genai 1.52.0. The SDK builds the Vertex host as https://${location}-aiplatform.googleapis.com/ (or the fixed global, us and eu hosts) and adds the model path by string concatenation. A location limited to [a-z][a-z0-9-]* therefore can't change the host. PROJECT_ENV_KEYS doesn't include GOOGLE_VERTEX_BASE_URL or GOOGLE_GEMINI_BASE_URL, so a project .env can't move the request somewhere else either. The model check adds % rejection on top of the SDK's own ../?/& rejection, which covers WHATWG %2e%2e dot segments.

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