Document runtime provider parameters

docs/internal/adapters.md

@@ -69,6 +69,8 @@ Primary app settings consumed by adapters:
 Execution profile/request settings used through runner:
 
 - `endpoint`, `model`, `temperature`, `max_tokens`, `top_p`, `timeout_seconds`, `service_tier`, `api_key_env`, `reasoning_effort`, `extra_params`
+- CLI and HTTP request adapters preserve caller intent for numeric runtime overrides. Omitted values remain absent; explicit zero values are mapped as explicit overrides.
+- HTTP `extra_params` accepts JSON-compatible values and maps them to domain request overrides without provider-specific adapter logic.
 
 ## External Dependencies
 
@@ -97,6 +99,10 @@ LLM adapter:
 - endpoint appends `/chat/completions`.
 - rendered messages without cache control serialize with string `content`.
 - rendered messages with cache control serialize as one text content block with `cache_control`.
+- non-empty `reasoning_effort` serializes as a top-level provider request field.
+- `extra_params` flatten into provider-specific top-level JSON request fields.
+- reserved `extra_params` keys are rejected before the provider call: `model`, `session_id`, `messages`, `temperature`, `max_tokens`, `top_p`, `service_tier`, `reasoning_effort`, and `response_format`.
+- empty `extra_params` keys and values that cannot be JSON-encoded are rejected before the provider call.
 - compatible cache usage response fields are parsed into domain token usage.
 - non-2xx responses map to request failure errors.
 - malformed responses (including missing/empty first choice content) are errors.
@@ -146,5 +152,5 @@ Behavior highlights:
 - Adapter packages do not own runner decision logic.
 - External request/response strictness is part of contract stability.
 - Prepared-render output never includes resolved API key values.
-- Outbound OpenAI-compatible request includes only currently serialized fields (`model`, optional `session_id`, `messages`, optional `temperature`, `max_tokens`, `top_p`, optional `service_tier`, optional `response_format`).
+- Outbound OpenAI-compatible request includes currently serialized first-class fields (`model`, optional `session_id`, `messages`, optional `temperature`, `max_tokens`, `top_p`, optional `service_tier`, optional `reasoning_effort`, optional `response_format`) plus validated `extra_params` flattened as provider-specific top-level fields.
 - Outbound cache control is message-level only; no top-level cache-control field is serialized.

docs/internal/runner.md

@@ -103,6 +103,7 @@ Validation content failures are not run errors:
    - built-in execution defaults
    - selected profile values
    - request overrides
+   - request numeric overrides are presence-aware, so omitted values preserve the current effective value and explicit zero values override it
 6. verify required `api_key_env` environment variable:
    - missing/empty env value returns an invalid request with `ErrAPIKeyEnvMissing`
    - only the environment-variable name is retained; secret value is never returned
@@ -115,6 +116,14 @@ Validation content failures are not run errors:
 
 `Prepare` does not call the LLM.
 
+Runtime target notes:
+
+- Profile `extra_params` and request `extra_params` carry JSON-compatible values through prepared output, run metadata, and `domain.GenerateRequest.Target`.
+- The OpenAI-compatible client serializes non-empty `reasoning_effort` as a top-level provider request field.
+- The OpenAI-compatible client flattens `extra_params` into provider-specific top-level JSON request fields.
+- Empty `extra_params` keys, reserved outbound field names, and values that cannot be JSON-encoded fail before the provider request.
+- Resolved API-key values are never stored in `PreparedRun`, `RunResult`, logs, or HTTP responses.
+
 ## Run Flow
 
 `Run` performs: