Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 1514-1518: When expectedThinkType == "" the test only checks
result.Thinking is nil but misses verifying result.OutputConfig; update the test
in the same block to also assert result.OutputConfig == nil (i.e., when
expectedThinkType is empty ensure both result.Thinking and result.OutputConfig
are nil) so regressions that set OutputConfig are caught; locate the assertion
block referencing expectedThinkType and result.Thinking in the test function and
add the OutputConfig nil check alongside it.
- Around line 1551-1656: The test
TestConvertResponsesRequestToAnthropic_ReasoningEffort is missing checks for
temperature clearing and OutputConfig being nil when no reasoning is applied;
update the test table to include the setTemperature (or expectNilTemp) boolean
like in TestConvertToAnthropicRequest_ReasoningEffort, then in the loop after
building req call convertResponsesRequestToAnthropic(req) and assert that when
expectNilTemp/setTemperature indicates temperature should be cleared the
result.Temperature is nil, and when tt.expectedThinkType == "" also assert
result.OutputConfig == nil; refer to convertResponsesRequestToAnthropic,
applyReasoning, and the test struct to locate where to add the new fields and
assertions.

In `@internal/providers/anthropic/anthropic.go`:
- Around line 91-94: The anthropicOutputConfig struct's Effort field currently
serializes empty strings as "effort":"" which can cause API rejections; update
the JSON tag on anthropicOutputConfig.Effort to include `omitempty` so empty
values are omitted from the payload (i.e., change the tag to
`json:"effort,omitempty"`), keeping the field name and type unchanged to
preserve call sites and behavior when a non-empty Effort is provided.
- Around line 108-110: The isAdaptiveThinkingModel function is too permissive
and can false-positive (e.g., "claude-4-60"); replace the simple Contains checks
with a precise match: either implement a compiled regex like `\b4[.-]6\b` and
test the model string with regexp.MatchString, or use an explicit allowlist of
canonical model names/prefixes (e.g., "claude-opus-4-6", "claude-sonnet-4-6")
and check membership; update isAdaptiveThinkingModel to use the chosen approach
and add unit tests for edge cases such as "claude-4-60", "claude-opus-4-6", and
"claude-opus-4-6x".

---

Outside diff comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 1658-1660: The function intPtr has its body unindented causing a
gofmt violation; inside the intPtr function (symbol: intPtr) indent the return
statement so the function body is properly formatted (i.e., place "return &i" on
a new line indented within the function block) and run gofmt/golangci-lint to
verify formatting.

In `@internal/providers/anthropic/anthropic.go`:
- Around line 415-439: The streaming path currently forwards every
content_block_delta immediately, causing preamble/whitespace blocks to be sent
to clients (inconsistent with extractTextContent non-streaming behavior); fix by
tracking the current content block type/index (set on content_block_start) and
only marshal/return deltas in the content_block_delta case when the block's
Index/Type matches the intended response block (e.g., the final
"thinking"/answer block) — update the state used in the switch handling
content_block_start and content_block_delta in anthropic.go (and mirror the same
gating logic in responsesStreamConverter.convertEvent) so preamble deltas are
skipped.

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 597-613: The function extractTextContent uses a redundant found
flag and a fallback to blocks[0].Text which is always empty for non-"text"
blocks; simplify by removing the found flag and the blocks[0].Text fallback:
iterate blocks ([]anthropicContent) and set last when b.Type == "text", then
after the loop just return last; update references to anthropicContent/Text
accordingly and remove any dead-branch logic related to the fallback.
- Around line 195-198: The current code unconditionally warns and clears
req.Temperature whenever it's non-nil, causing spurious warnings for a value of
1.0; update the guard around req.Temperature so it only logs and sets
req.Temperature = nil when the dereferenced value is present and not equal to
1.0 (i.e., if req.Temperature != nil && *req.Temperature != 1.0) and keep the
slog.Warn and clearing behavior only in that branch to avoid noisy logs when
temperature==1.0; reference req.Temperature and slog.Warn in anthropic.go to
locate and change the conditional.

---

Outside diff comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 201-213: The function reasoningEffortToBudgetTokens currently maps
unknown efforts (including "max") to 5000 tokens; add an explicit case for "max"
that returns the highest budget (match "high"/max budget, e.g., 20000) and
change the default branch to warn and return the high/max budget instead of
defaulting to low. Update the slog.Warn message in reasoningEffortToBudgetTokens
to reflect that an inappropriate effort was provided and that you're falling
back to the highest budget.

---

Duplicate comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 108-110: The isAdaptiveThinkingModel function currently uses
strings.Contains(model, "4-6") and strings.Contains(model, "4.6") which causes
false positives (e.g., "claude-4-60"); update this to perform a bounded match or
use an explicit allowlist: replace the substring checks in
isAdaptiveThinkingModel with a regex match using word boundaries like
`\b4[.-]6\b` (or implement an allowlist of exact model names) so only exact
"4-6" or "4.6" tokens are matched; keep the function name
isAdaptiveThinkingModel and ensure you import/use the regex utilities
accordingly.

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 666-737: Add a test case to TestExtractTextContent that covers the
scenario where all blocks are "thinking" (no "text" blocks) to assert
extractTextContent returns an empty string; specifically add an entry like name:
"only thinking blocks - returns empty" with blocks: []anthropicContent{{Type:
"thinking", Text: ""}} and expected: "" so extractTextContent's fallback
behavior (falling back to blocks[0].Text) is explicitly tested.

In `@internal/providers/anthropic/anthropic.go`:
- Around line 185-210: The adaptive branch in applyReasoning currently sets
req.OutputConfig.Effort directly (for models where
isAdaptiveThinkingModel(model) is true) allowing invalid effort strings to reach
Anthropic; validate the effort the same way as the legacy branch by running the
input through the existing reasoningEffortToBudgetTokens (or a shared
validateEffort function) to map/normalize invalid values to the default (e.g.,
"low"), assign the validated value to req.OutputConfig.Effort, and emit a
warning via slog.Warn when the original effort was invalid/normalized so callers
get a clear gateway-side message.

---

Outside diff comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 415-497: The streaming converter (streamConverter.convertEvent) is
emitting all content_block_delta text chunks including preamble whitespace from
non-final text blocks; track the current content block type on
content_block_start (e.g., add a field like sc.currentContentType or
sc.inTextBlock and update it in the "content_block_start" case) and only emit
content_block_delta when the block is a text block you intend to forward;
additionally, filter out deltas whose Text is only whitespace (trim and skip) to
match the non-streaming extractTextContent behavior so leading "\n\n" preambles
are not streamed.

---

Duplicate comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 206-209: The guard currently warns and clears any non-nil
req.Temperature unconditionally; change it to only warn and clear when
req.Temperature is non-nil and not equal to 1.0 (the special API-required value
for "thinking"), so keep the temperature untouched when it equals 1.0. Locate
the check around req.Temperature in anthropic.go and update the conditional to
verify the dereferenced temperature value before logging and setting it to nil.
- Around line 605-624: The helper extractTextContent can be simplified by
removing the unused boolean "found": in the loop over blocks of type
anthropicContent set last = b.Text whenever b.Type == "text", then after the
loop return last if last != "" else if len(blocks) > 0 return blocks[0].Text
else return ""; update the function extractTextContent to use only last, blocks,
Type and Text (no found flag) and preserve the legacy fallback to
blocks[0].Text.

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 1360-1368: Test currently checks len(result.Output) but then
indexes result.Output[0].Content[0] which can panic if Content is empty; update
the test (around the assertions using result.Output, result.Output[0].Content,
and result.Usage) to first assert len(result.Output[0].Content) > 0 (or
otherwise check Content length) before accessing Content[0].Text so the test
fails with a clear error rather than panicking; reference the values produced by
convertAnthropicResponseToResponses and add an explicit error message if Content
is empty.
- Around line 654-663: The test currently indexes result.Choices[0] in the
convertFromAnthropicResponse test without verifying the slice length; add a
guard before that access in the test: check len(result.Choices) == 0 and call
t.Fatalf (or t.Errorf followed by return) with a clear message like "no choices
returned" so the test fails with a descriptive error instead of panicking;
update the block around convertFromAnthropicResponse and the subsequent
assertions (Choices[0].Message.Content and Usage.CompletionTokens) to run only
after the non-empty check.

In `@internal/providers/anthropic/anthropic.go`:
- Around line 185-188: The doc comment currently above normalizeEffort actually
describes applyReasoning; move or rewrite that comment so it immediately
precedes the applyReasoning function (and remove or replace the incorrect
comment over normalizeEffort). Specifically, relocate the block starting with
"applyReasoning configures thinking and effort on an anthropicRequest..." from
above normalizeEffort to directly above the applyReasoning function declaration,
and ensure normalizeEffort has an appropriate short comment (or none) so go doc
attributes the documentation to the correct function names normalizeEffort and
applyReasoning.
- Around line 108-112: The adaptiveThinkingPrefixes slice currently includes
"claude-haiku-4-6" which is unsupported for adaptive thinking; remove that entry
from adaptiveThinkingPrefixes so it contains only "claude-opus-4-6" and
"claude-sonnet-4-6", and update any nearby comment or validation that references
adaptive thinking support (functions that check adaptiveThinkingPrefixes) to
ensure they only target supported model IDs (adaptiveThinkingPrefixes).
- Around line 188-196: Add a clarifying comment above normalizeEffort explaining
that although Anthropic Opus 4.6 supports "max", the gateway's public type
core.Reasoning.Effort only exposes "low", "medium", and "high", so "max" is
intentionally rejected and any unsupported value is downgraded to "low" (keep
the existing switch behavior and slog.Warn). Reference normalizeEffort and
mention "max" and Opus 4.6 in the comment so future readers understand why the
gateway rejects "max".

---

Outside diff comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 436-460: The streaming converter forwards every non-empty
content_block_delta (in streamConverter.convertEvent and
responsesStreamConverter.convertEvent), which causes preamble "text" blocks
(e.g. "\n\n") to be emitted before hidden "thinking" blocks; fix this by adding
state tracking on the stream converter (e.g., fields like
currentContentBlockType string and seenThinkingInMessage bool on the
streamConverter struct instance sc), set currentContentBlockType when handling
"content_block_start" events, set seenThinkingInMessage=true when you see a
"thinking" start, and in the "content_block_delta" handler only emit "text"
deltas if either the block type is not "text" or seenThinkingInMessage is true
(suppress text deltas that are a preamble before any thinking); reset the flags
at message end/new message start to avoid cross-message leakage.

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 1384-1578: Add a test case to
TestConvertToAnthropicRequest_ReasoningEffort that verifies temperature == 1.0
is preserved when reasoning is enabled: extend the test table to include a field
(e.g., temperatureVal float64 or a boolean like setTempOne) and add an entry
such as "legacy model - preserves temperature=1.0 with reasoning" for model
"claude-3-5-sonnet-20241022" with reasoning Effort "medium", expectedThinkType
"enabled", expectedBudget 10000, expectedMaxTokens 15000 and expectNilTemp
false; in the test loop, set req.Temperature to &temperatureVal (use 1.0 when
the new flag is true) before calling convertToAnthropicRequest and assert
result.Temperature is non-nil and equals 1.0 to exercise the applyReasoning
branch that preserves temperature==1.0.
- Around line 1384-1578: The test suite
TestConvertToAnthropicRequest_ReasoningEffort lacks a case for temperature ==
1.0; add a case to ensure applyReasoning preserves temperature==1.0 when
reasoning is enabled. Extend the test table (in
TestConvertToAnthropicRequest_ReasoningEffort) with either a new field like
temperature float64 (default 0.7) or a boolean setTemperatureOne, add the test
case named "legacy model - preserves temperature=1.0" with model
"claude-3-5-sonnet-20241022", reasoning {Effort:"medium"}, maxTokens 15000,
expectedThinkType "enabled", expectedBudget 10000, expectedMaxTokens 15000 and
expectNilTemp false; update the loop that sets req.Temperature to use the new
temperature value (1.0 for this case) so convertToAnthropicRequest and
applyReasoning are exercised with temperature == 1.0.

---

Outside diff comments:
In `@internal/providers/anthropic/anthropic.go`:
- Around line 437-464: The stream converter currently emits every
content_block_delta with non-empty Delta.Text, causing preamble_text to be
forwarded; update the handler around the
"content_block_start"/"content_block_delta" cases to track the active block type
(use event.ContentBlock in the "content_block_start" case, store it on the
stream converter state e.g., sc.activeContentBlock, and clear it on
content_block_end), and only marshal/return text chunks in the
"content_block_delta" case when the active block is the final answer block
(e.g., "answer" or "answer_text") — apply the same guarded logic to
responsesStreamConverter so only answer text is streamed to clients.
- Around line 437-464: The streaming converter (convertEvent / streamConverter
handling of "content_block_delta") is emitting every text delta including
Anthropic's preamble text block, causing leading whitespace; change
streamConverter to track content block sequence/type and suppress non-final text
blocks by recording the current content block kind on "content_block_start" and
only emitting text deltas for the final text content block (or emit text deltas
only after seeing the final block's start or the "end_turn" stop anchor), e.g.,
add a field on streamConverter to store the active content block type/index,
update it on "content_block_start"/"content_block_start"/other start events, and
in the "content_block_delta" branch only marshal/return the delta when the
active block is the final text block (or when end_turn is reached). Ensure you
reference convertEvent, streamConverter, and extractTextContent when
implementing this logic.

---

Duplicate comments:
In `@internal/providers/anthropic/anthropic_test.go`:
- Around line 1580-1734: The test suite misses coverage for temperature == 1.0:
in TestConvertResponsesRequestToAnthropic_ReasoningEffort the helper always sets
temp := 0.7, so add a new test case entry in the tests slice that sets
setTemperature true but uses temperature 1.0 (e.g., model "claude-opus-4-6" with
Reasoning non-nil like Effort "high"), set expectNilTemp to false and
appropriate expectedThinkType/expectedEffort/expectedMaxTokens; run the same
assertions (via convertResponsesRequestToAnthropic) to ensure result.Temperature
is non-nil when temperature == 1.0 and reasoning is enabled. Ensure the new case
is added alongside existing cases in
TestConvertResponsesRequestToAnthropic_ReasoningEffort.
- Around line 1580-1733: Add a test row to
TestConvertResponsesRequestToAnthropic_ReasoningEffort that exercises a
Temperature explicitly set to 1.0 so it is preserved (expectNilTemp=false):
create a case (e.g. name "temperature 1.0 preserved") with Model like
"claude-3-5-sonnet-20241022", Reasoning nil, MaxOutputTokens intPtr(1000),
setTemperature true (and in the test set temp := 1.0 on the Requests
Temperature), and expectedMaxTokens 1000 and expectNilTemp false; this verifies
convertResponsesRequestToAnthropic preserves a Temperature of 1.0 on
core.ResponsesRequest.