HKUDS/Vibe-Trading · error · ValueError

evidence text cannot be empty

Error message

evidence text cannot be empty

What it means

append_evidence strips the evidence text and raises ValueError('evidence text cannot be empty') when nothing remains — an evidence row must carry actual content to be usable in goal audits. The check runs inside a write transaction after the goal is confirmed mutable and IDs resolved.

Source

Thrown at agent/src/goal/store.py:632

            goal_id: Goal being mutated.
            expected_goal_id: Goal id captured at the start of the agent turn.
            evidence: Evidence payload.

        Returns:
            Persisted evidence record.

        Raises:
            StaleGoalError: If the expected goal id does not match or goal is not current.
            ValueError: If evidence text is empty or references an unknown criterion.
        """
        evidence_id = _id("ev")
        with self._write_transaction():
            goal = self._require_mutable_goal(session_id, goal_id, expected_goal_id)
            session_id = goal.session_id
            goal_id = goal.goal_id
            text = evidence.text.strip()
            if not text:
                raise ValueError("evidence text cannot be empty")
            if evidence.criterion_id is not None:
                self._require_criterion(goal.goal_id, evidence.criterion_id)
            if evidence.claim_id is not None:
                self._require_claim(goal.goal_id, evidence.claim_id)

            now = _now_iso()
            freshness_status = "fresh" if evidence.data_as_of else "unknown"
            verification_status = self._verification_status(evidence)
            self._conn.execute(
                """
                INSERT INTO goal_evidence (
                    evidence_id, goal_id, session_id, criterion_id, claim_id,
                    evidence_type, text, tool_call_id, run_id, source_provider,
                    source_type, source_uri, symbol_universe_json, benchmark_json,
                    timeframe, method, assumptions_json, artifact_path,
                    artifact_hash, retrieved_at, data_as_of, freshness_status,
                    verification_status, confidence, caveat,
                    contradicts_claim_ids_json, created_at

View on GitHub (pinned to 80ffdda44c)

Solutions

1. Ensure evidence.text is a non-blank string before calling append_evidence
2. In agent loops, skip logging when the captured output is empty rather than recording it
3. Strip and check in the caller: if not text.strip(): return/skip
4. If evidence is genuinely empty (e.g. empty command output), record a descriptive placeholder like '(no output)'

Example fix

# before
store.append_evidence(session_id, goal_id, EvidenceRecord(text="   "))
# after
if output.strip():
    store.append_evidence(session_id, goal_id, EvidenceRecord(text=output.strip()))

text = (evidence_text or '').strip()
if not text:
    # skip logging instead of raising downstream
    logging.debug('skipping empty evidence')
else:
    store.append_evidence(session_id, goal_id, EvidenceRecord(text=text))

def is_valid_evidence(text: str) -> bool:
    return isinstance(text, str) and bool(text.strip())

try:
    store.append_evidence(session_id, goal_id, ev)
except ValueError as e:
    if 'cannot be empty' in str(e):
        pass  # intentionally skip blank evidence
    else:
        raise

When it happens

Trigger: Calling append_evidence with evidence.text='' or whitespace-only (' ', '\n'); agent flows (cmd_evidence / add_goal_evidence) forwarding a file read that came back empty or a generated summary that was blank.

Common situations: Automated agents logging evidence from tool output that can be empty; templates producing whitespace-only strings; UI optional textareas submitted empty; tests asserting rejection of blank evidence.

Related errors

• {field_name} cannot be empty
• at least one goal criterion is required
• {name} must be positive
• evidence limit must be positive
• usage deltas must be non-negative

AI-assisted analysis of HKUDS/Vibe-Trading@80ffdda44c (2026-08-28). Data as JSON: /api/errors/f4250fd7809aec87. Report an issue: GitHub.