[EkoSaputro14]

Summary

This PR fixes tool-calling failures and text corruption when using deepseek-web/deepseek-v4-flash or deepseek-web/deepseek-v4-pro.

Root Cause

DeepSeek V4 (particularly on chat.deepseek.com) natively emits DSML (DeepSeek Markup Language) markup or hybrid ad-hoc tags during tool invocations:

1. DSML Tag Leaks: The model emits <｜｜DSML｜｜ calls>, <｜｜DSML｜｜ invoke name="...">, and <｜｜DSML｜｜ parameter name="..."> using fullwidth vertical bars (｜). OmniRoute's TAG_TOKEN_RE only looked for <tool> and <tool_call>, causing the entire DSML block to be treated as plain message content.
2. Web Disclaimer Leak: DeepSeek appends "This response is AI-generated, for reference only." at the end of outputs.
3. Hallucinated Closing Parameter Tag: The model frequently produces valid JSON followed by an invalid closing tag: <tool>{"name": "...", "arguments": {...}}</parameter></tool>. Because of the trailing </parameter>, JSON.parse failed with SyntaxError.
4. Bare Parameter Blocks: On long agentic trajectory prompts (e.g. 30k+ tokens in coding agents), the model occasionally skips the enclosing <tool> or <invoke> wrapper and outputs bare <parameter name="...">...</parameter> blocks directly.

Solution

In open-sse/translator/deepseekWebTools.ts:

• Stripped web disclaimer string.
• Stripped outer DSML envelope tags (<｜｜DSML｜｜ calls>, etc.).
• Normalized <invoke> tags into <tool> and <parameter> tags into canonical parameter format.
• Stripped trailing hallucinated </parameter> closing tags right after JSON closing braces (}).
• Auto-wrapped bare <parameter> sequences into <tool>...</tool> so that OmniRoute's existing schema-based nameless-block matcher can map the parameter to the requested tool.

Testing & Verification

Tested against live prompts with Hermes Agent:

• Verified parallel tool calling with <｜｜DSML｜｜ invoke> (e.g. vision_analyze + terminal).
• Verified bare <parameter name="code"> correctly maps to execute_code.
• Verified streaming SSE (stream: true) correctly emits structured tool_calls chunks without XML tag leakage.

[Copilot]

🟡 Changes recommended

Unresolved parsing issues could corrupt or leak tool-call content, and regression tests are missing.

Get a fresh assessment by requesting another Copilot review.

Pull request overview

Updates DeepSeek Web tool-call parsing for V4 DSML markup and bare parameter blocks.

Changes:

• Normalizes DSML tags and supports bare parameters.
• Handles disclaimers and malformed closing tags.
• Review identified unresolved parsing issues and missing regression tests.

File summaries

File	Summary
open-sse/translator/deepseekWebTools.ts	Adds DeepSeek V4 markup normalization and bare-parameter handling.

Review details

Suppressed comments (3)

open-sse/translator/deepseekWebTools.ts:447

• The native DSML envelope uses function_calls, but this alternation only removes calls and tool_calls. The inner <...invoke> block will still be parsed, while the unmatched <｜DSML｜function_calls> / closing tags remain in content after the accepted tool range is stripped, so the reported markup leak is not fully fixed. Include function_calls in the envelope alternatives.

    .replace(/<\/?(?:[｜|]{1,2})DSML(?:[｜|]{1,2})\s*(?:calls|tool_calls)>/gi, "")

open-sse/translator/deepseekWebTools.ts:451

• The unconditional .trim() changes the no-tag fallback contract: a normal reply such as " answer " is returned as "answer", whereas parseToolCallsFromText preserves the original text when no tool tags are present. Preserve surrounding text for plain replies and limit trimming to the tool-normalization path if it is required there.

    .trim();

open-sse/translator/deepseekWebTools.ts:446

• This global replacement also runs inside tool payloads, so a legitimate argument containing this sentence is silently corrupted before JSON parsing (for example, a message value equal to the disclaimer becomes empty). Restrict the cleanup to a trailing provider footer, such as an end-anchored match, rather than replacing every occurrence.

    .replace(/This response is AI-generated, for reference only\./g, "")

• Files reviewed: 1/1 changed files
• Comments generated: 2
• Review effort level: Lite

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[EkoSaputro14]

Note regarding #13345

Cross-referencing #13345 by @espokaos-ops:

While #13345 addresses the core native DSML <calls> / <invoke> / <parameter> envelope translation, this PR was developed against real production agentic coding traces (Hermes Agent with 30k+ token trajectories) and specifically covers three additional edge cases observed in live DeepSeek V4 web traffic:

1. Bare Parameter Blocks (Omitted Enclosing Tags):
   In heavy multi-turn contexts, the model occasionally skips both <tool> and <invoke> wrappers entirely, emitting bare <parameter name="...">...</parameter> blocks directly (e.g. <parameter name="code">...</parameter>). This PR wraps those bare blocks so OmniRoute's existing nameless-block schema matching (buildSchemaParamMap) can resolve them to the target tool (e.g., execute_code).
2. Hallucinated Trailing Closers (}}</parameter></tool>):
   The model frequently produces valid JSON followed immediately by a hallucinated closing tag: <tool>{"name": "...", "arguments": {...}}</parameter></tool>. Without stripping (}\s*)<\/(?:parameter|invoke|arguments)>, JSON.parse fails with a SyntaxError and drops the tool call.
3. Web Disclaimer Leak:
   DeepSeek Web appends "This response is AI-generated, for reference only." at the end of generations, which leaked into the output unless cleaned.

Whether this is reviewed as a standalone patch or incorporated into #13345, these patterns are critical to avoid silent tool drops during agentic coding sessions.

[EkoSaputro14]

Thank you @copilot-pull-request-reviewer for the thorough and high-quality review!

All points have been addressed in commits 8647b38 and 6910975:

1. Envelope regex alternation: Added function_calls to envelope cleaning (<｜DSML｜function_calls>, etc.).
2. Preserve plain text formatting: Guarded the normalization pipeline with a marker preflight check (/[｜|]{1,2}DSML[｜|]{1,2}/i, /<parameter\b/i, disclaimer text, etc.). Plain responses without tool tags are preserved verbatim, maintaining original whitespace and indentation contract.
3. Anchor disclaimer cleanup: Restricted disclaimer removal to trailing footer matches (/\s*This response is AI-generated, for reference only\.\s*$/i), preventing accidental argument corruption if the disclaimer phrase appears inside tool parameters.
4. Regression test suite: Added comprehensive automated tests in tests/unit/deepseek-web-v4-dsml.test.ts covering:
   • Plain text whitespace preservation
   • Native DSML <calls> / <invoke> with fullwidth bars
   • Envelope with function_calls
   • Disclaimer inside tool payload vs trailing disclaimer
   • Bare <parameter> auto-wrapping and schema matching
   • Hallucinated }}</parameter></tool> closing tag recovery

All 6 test cases pass cleanly. Ready for re-review!