Lift the prompt-cache policy out of OpenCode's bridge and into the
LLM package as a typed, gated patch. The policy mirrors the AI-SDK
applyCaching path (packages/opencode/src/provider/transform.ts:229):
mark the first 2 system parts and the last 2 messages with an
ephemeral cache hint, gated on `model.capabilities.cache.prompt`.
Adapters lower the hint structurally — Anthropic emits
`cache_control: { type: "ephemeral" }` on the marked block,
Bedrock emits a positional `cachePoint: { type: "default" }`
after the marked block (added in 9d7d518ac). The capability gate
keeps non-cache adapters (OpenAI Responses, Gemini, OpenAI-compat
Chat) hint-free.
Why a Patch and not bridge code:
- packages/llm/AGENTS.md TODO explicitly calls for cache hint patches
- Other consumers of @opencode-ai/llm get caching for free
- The bridge stays focused on shape conversion (MessageV2 \u2192 LLMRequest)
- Patches compose via ProviderPatch.defaults (now includes this one)
- The capability gate is a typed predicate, not provider-name matching
Implementation:
- New `cachePromptHints` patch in provider/patch.ts. The
`withCacheOnLastText` helper uses Array.findLastIndex (codebase
idiom) and short-circuits when no text part exists so messages
with only tool-result content are returned identity-equal.
- `EPHEMERAL_CACHE` is a single shared CacheHint instance — no
per-request allocation, preserves `instanceof` for any consumer
that checks class identity.
- Added to `ProviderPatch.defaults` so existing callers that pass
`defaults` get cache support automatically.
Tests (5 new in patch.test.ts):
- Marks first 2 system parts on cache-capable models.
- Marks last text part of last 2 messages.
- Targets the last text part when a message has trailing
non-text content (assistant text + tool-call).
- Returns content unchanged (identity-equal) when no text part
exists, so pure tool-result messages don't allocate.
- No-op when the model does not advertise prompt caching.
Bridge cleanup:
- Removed `applyCachePolicy`, `withCacheOnLastText`,
`updateMessageContent`, `EPHEMERAL_CACHE` from llm-native.ts
(-30 lines of bridge-side cache code).
- Dropped now-unused `CacheHint`, `LLMRequest`, `Message` imports.
- The bridge's only responsibility is now MessageV2 lowering;
callers wire `patches: ProviderPatch.defaults` at client
construction.
OpenCode tests rewritten:
- Old: assert on `request.system[N].cache` (bridge internals).
- New: assert on `prepared.target` after running through
`LLMClient.make({ adapters, patches: ProviderPatch.defaults })
.prepare(request)` — verifies the full lowering end-to-end.
- Anthropic: target.system[0..1] carry `cache_control: ephemeral`,
target.messages[1..2] carry it on the final text block.
- Bedrock: target has `cachePoint` markers after each cached block.
- Non-cache (OpenAI Responses): JSON.stringify(target) contains
none of `cache_control` / `cachePoint` / `ephemeral`.
Verified: bun typecheck clean across both packages, 120/0/0 in LLM
package (was 113; +7 from new patch tests counting parameter
variations), 21/0/0 in OpenCode native+bridge tests.
Implements the AWS Bedrock Converse streaming protocol as the 5th
first-class adapter in @opencode-ai/llm. Single `bedrock-converse`
adapter covers all underlying models (Anthropic, Llama, Mistral,
Cohere, Nova, Titan) since Converse is uniform.
Wire format: messages with text / reasoning / toolUse / toolResult
content blocks, system blocks, inferenceConfig, toolConfig with
toolSpec + toolChoice. Image / document / cache-point content types
are still TODO.
Streaming: AWS event stream binary framing via @smithy/eventstream-codec.
Each frame is decoded then dispatched by `:event-type` header into
the chunk schema. Bedrock splits the finish across `messageStop`
(reason) and `metadata` (usage) — the parser stashes the reason and
emits a single consolidated `request-finish` event when metadata
arrives, with an `onHalt` fallback for truncated streams.
Auth: two paths. Bearer API key (newer) when the consumer sets
`model.headers.authorization = 'Bearer <key>'`. SigV4 signing via
aws4fetch otherwise — credentials live on `model.native.aws_credentials`
and are signed at `toHttp` time so STS-vended tokens are picked up
when the consumer rebuilds the model. The adapter rejects requests
with neither auth path with a clear InvalidRequestError.
Routing: `@ai-sdk/amazon-bedrock` lowers to `bedrock-converse` via
the new `AmazonBedrock` provider routing module; the OpenCode
`llm-bridge.ts` registers it.
Cassette format: response bodies under
`application/vnd.amazon.eventstream` and `application/octet-stream`
content types are now stored as base64 with `bodyEncoding: 'base64'`
on the response snapshot — text round-tripping mangled the CRC32
fields in event-stream frames. Existing cassettes (SSE/JSON) omit
the field and decode as text unchanged.
Tests: 11 deterministic fixtures (prepare / lower messages / lower
tool config / decode text+usage / decode tool calls / decode
reasoning / decode throttling exception / auth path validation /
SigV4 plumbing) + 2 recorded cassettes against live Bedrock
(`us.amazon.nova-micro-v1:0` in us-east-1) for streaming text and
streaming tool calls.
AGENTS.md: documents the Bedrock auth model, binary cassette format,
and updates the protocol coverage / cassette backlog.
Deps: @smithy/eventstream-codec, @smithy/util-utf8, aws4fetch (~40KB
combined; matches AI SDK's approach).
The bash tool description now explicitly states that the temp directory has already been created and exists, preventing agents from unnecessarily trying to create it before use.
- Removed @effect/language-service from both packages/core and packages/opencode tsconfig files and dependencies
- Wrapped mergeDeep calls in config loading and LLM streaming to avoid expensive remeda conditional merge type instantiations in hot paths
- Narrowed Drizzle migrate() overload signature to avoid expensive variance checks during database initialization
These changes reduce TypeScript type-checking overhead and improve startup and runtime performance for config loading, LLM streaming, and database migrations.
Kit Langton