fix(tools): defensively recover concatenated streamed tool arguments#66
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walcz-de wants to merge 1 commit into
Open
fix(tools): defensively recover concatenated streamed tool arguments#66walcz-de wants to merge 1 commit into
walcz-de wants to merge 1 commit into
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When streamed tool-call argument deltas are accumulated into Function.Arguments, some
providers (e.g. an OpenAI-compat proxy that maps Anthropic/Gemini tool-call streaming into
OpenAI deltas) re-emit the full arguments object, so the accumulated string becomes a
concatenation like {"a":1}{"a":1}. A plain json.Unmarshal then fails with
'invalid character { after top-level value' and the tool loop cannot proceed — agentic
tool calling through such providers is unusable, while local backends with correct
incremental deltas are unaffected.
Recover the FIRST complete top-level JSON object via json.Decoder on that specific failure;
the happy path keeps the direct Unmarshal. Adds parseStreamedToolArgs + a regression test
(plain / concatenated-duplicate / concatenated-different / malformed) and routes both the
streaming and non-streaming parse sites through it.
Signed-off-by: stefanwalcz <stefan.walcz@walcz.de>
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Problem
When streamed tool-call argument deltas are accumulated into
Function.Arguments, some providers re-emit the full arguments object rather than incremental fragments — most notably an OpenAI-compatible proxy that maps Anthropic/Gemini tool-call streaming into OpenAIdelta.tool_calls. The accumulated string then becomes a concatenation, e.g.{"a":1}{"a":1}.json.Unmarshalrejects that withinvalid character '{' after top-level value, sodecisionWithStreaming/ the non-streaming path setallParsed = falseand the tool loop cannot proceed. Result: agentic tool-calling is unusable through such providers, while local backends that emit correct incremental deltas are unaffected.Fix
Add
parseStreamedToolArgswhich keeps the directjson.Unmarshalfast path and, only on failure, recovers the first complete top-level JSON object viajson.Decoder. Both parse sites (streaming + non-streaming) route through it. Truly malformed input still returns an error (no silent garbage).Test
parse_defensive_test.gocovers: plain-valid, concatenated-duplicate, concatenated-different (first wins), malformed (errors).Signed-off-by included (DCO).