Support base64 embedding responses in the Rust SDK

[AnthonyRonning]

Summary

• model embedding response values as either float vectors or base64 strings
• preserve the requested representation through SDK deserialization and serialization
• add ergonomic accessors for both representations
• add SDK contract and encrypted live integration coverage for both float and base64

Why

Tinfoil already supports encoding_format: "base64", and OpenSecret already preserves that provider response through its encrypted embeddings endpoint. The Rust SDK currently requires every embedding value to deserialize as Vec<f64>, causing otherwise valid base64 responses to fail before Maple Proxy can return them.

This fixes the response model at the SDK layer. No OpenSecret backend or Maple Proxy behavior change is needed.

Compatibility

This changes the Rust representation of EmbeddingData.embedding from Vec<f64> to EmbeddingVector. Consumers upgrading the SDK and directly reading that field can match the enum or use as_floats() / as_base64(). The HTTP API and wire format are unchanged.

Testing

• cargo test --lib --all-features — 32 passed
• cargo clippy --all-targets --all-features -- -D warnings
• encrypted live SDK test with encoding_format: "float" — 768 finite values
• encrypted live SDK test with encoding_format: "base64" — valid base64 decoding to 768 float32 values

Related to OpenSecretCloud/maple-proxy#40.

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Summary by CodeRabbit

• New Features
  • Embedding responses can now be returned as either float arrays or base64-encoded values.
  • Added helpers to read embeddings in the requested representation.
  • Clients can request explicit float or base64 embedding encoding modes.
• Bug Fixes
  • Improved handling by rejecting unsupported/unknown embedding response shapes during parsing.
• Tests
  • Expanded integration coverage for both encoding formats, including dimensionality, decoding, and usage metadata.
• Chores
  • Bumped the Rust crate version to 3.3.0.

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ℹ️ Recent review info

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Configuration used: Organization UI

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Run ID: 7b5bda95-e03f-4a65-abc7-f0223ff4b816

📥 Commits

Reviewing files that changed from the base of the PR and between d675372 and 3ba56e6.

📒 Files selected for processing (1)

• rust/Cargo.toml

✅ Files skipped from review due to trivial changes (1)

• rust/Cargo.toml

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📝 Walkthrough

Walkthrough

Rust embedding types now accept float-array or base64-string wire representations. Unit and integration tests validate both formats, accessor behavior, serialization, dimensions, decoded byte lengths, finiteness, and usage fields. The Rust package version is updated to 3.3.0.

Changes

Embedding format support

Layer / File(s)	Summary
Embedding vector contract rust/src/types.rs	Adds the untagged EmbeddingVector enum and accessors, updates EmbeddingData.embedding, and tests both supported representations plus invalid object input.
Encoding-specific integration coverage rust/tests/ai_integration.rs	Adds float and base64 encoding tests and updates multi-input and string-conversion assertions to use the new accessors.
Package version update rust/Cargo.toml	Bumps the package version from 3.2.0 to 3.3.0.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• OpenSecretCloud/OpenSecret-SDK#59: Introduced the embeddings API surface extended by these type and integration-test changes.

Poem

A bunny found two ways to hop,
Through floating fields or strings on top.
It checked each byte and number bright,
Then nibbled tests by moonlit light.
“Both forms deserialize right!”

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title matches the main SDK change, though it only mentions base64 and omits the new float-vector representation support.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex-embeddings-api-investigation-opensecret-sdk

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

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