feat(server): parse <function_calls> XML tool emissions

[dpavlin]

Summary

Adds support for parsing <function_calls><invoke name="...">...</invoke></function_calls> tool call containers emitted by DeepSeek models during multi-tool and file-reading operations.

Changes

1. Tool Parser (tool_parser.cpp):
   • Registers <function_calls> opener in find_tool_syntax_start and holdback calculation.
   • Adds Pattern 4d to parse <function_calls> containers, extracting XML <param name="...">...</param> and inline JSON bodies.
   • Coerces string parameters according to JSON Schema property definitions.
2. Streaming Emitter (sse_emitter.cpp):
   • Intercepts <function_calls> occurring in StreamMode::REASONING to buffer tool calls without leaking into reasoning stream.
   • In emit_finish, splits parsed.cleaned_text across </think> to maintain clean separation between reasoning and content deltas.
3. Unit Tests (test_server_unit.cpp):
   • Adds unit tests covering XML parameter extraction, inline JSON bodies, and thinking-mode streaming.

Verification

• 364 / 364 unit tests pass (ctest -R test_server_unit).
• Verified live streaming inference with DeepSeek-V4-Flash-ROCMFP2-STRIX on ROCm hardware.

[dpavlin]

@cubic-dev-ai review

[cubic-dev-ai]

@cubic-dev-ai review

@dpavlin I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

2 issues found across 3 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="server/src/server/tool_parser.cpp">

<violation number="1" location="server/src/server/tool_parser.cpp:1203">
P2: A malformed/single-source JSON body inside <invoke> is silently ignored (no call, no error), so in a multi-invoke <function_calls> block one bad JSON invoke is dropped while valid siblings still execute; an empty '{}' body also produces a zero-argument call. Parse defensively and collect per-invoke errors or skip only the malformed invoke while reporting the rest.</violation>

<violation number="2" location="server/src/server/tool_parser.cpp:1223">
P2: When an invoke body contains a truncated parameter or extra non-parameter text, Pattern 4d still emits a tool call with partial arguments and removes the entire block. Validate that parameter matches cover the complete body and reject duplicate keys before queuing the call, as the existing strict XML parser does.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P2: When an invoke body contains a truncated parameter or extra non-parameter text, Pattern 4d still emits a tool call with partial arguments and removes the entire block. Validate that parameter matches cover the complete body and reject duplicate keys before queuing the call, as the existing strict XML parser does.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At server/src/server/tool_parser.cpp, line 1223:

<comment>When an invoke body contains a truncated parameter or extra non-parameter text, Pattern 4d still emits a tool call with partial arguments and removes the entire block. Validate that parameter matches cover the complete body and reject duplicate keys before queuing the call, as the existing strict XML parser does.</comment>

<file context>
@@ -1174,6 +1177,59 @@ ToolParseResult parse_tool_calls(const std::string & text, const json & tools) {
+                        args[k] = convert_param_value(v, k, find_tool_properties(tools, fn_name));
+                    }
+                }
+                block_calls.push_back({fn_name, std::move(args)});
+            }
+
</file context>

[cubic-dev-ai]

P2: A malformed/single-source JSON body inside is silently ignored (no call, no error), so in a multi-invoke <function_calls> block one bad JSON invoke is dropped while valid siblings still execute; an empty '{}' body also produces a zero-argument call. Parse defensively and collect per-invoke errors or skip only the malformed invoke while reporting the rest.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At server/src/server/tool_parser.cpp, line 1203:

<comment>A malformed/single-source JSON body inside <invoke> is silently ignored (no call, no error), so in a multi-invoke <function_calls> block one bad JSON invoke is dropped while valid siblings still execute; an empty '{}' body also produces a zero-argument call. Parse defensively and collect per-invoke errors or skip only the malformed invoke while reporting the rest.</comment>

<file context>
@@ -1174,6 +1177,59 @@ ToolParseResult parse_tool_calls(const std::string & text, const json & tools) {
+                if (!tool_allowed(tools, fn_name)) continue;
+                std::string body = trim_ws((*it)[2].str());
+                json args = json::object();
+                if (!body.empty() && body.front() == '{') {
+                    json raw_args = json::parse(body, nullptr, false);
+                    if (raw_args.is_discarded() || !raw_args.is_object()) continue;
</file context>

[cubic-dev-ai]

2 existing issues remain and no new issues found across 3 files

<sub>Requires human review: Auto-approval blocked by 6 unresolved issues from previous reviews.

Re-trigger cubic</sub>

[cubic-dev-ai]

1 existing issue remains and no new issues found across 4 files (changes from recent commits).

<sub>Requires human review: Auto-approval blocked because this review re-detected 1 unresolved issue already reported by Cubic.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>