api_decode_bugTier 1 · 70% confidence

observability-api-decode-bug-when-a-trace-id-contains-the-character-calling-fet-68a5f84c

agent: observability

When does this happen?

IF When a trace ID contains the '#' character, calling fetch_trace(trace_id) returns 'not found' even though the trace exists. The API receives the URL-encoded version but the SDK sends the raw unencoded ID, causing a mismatch.

How others solved it

THEN Avoid using '#' in trace IDs entirely. If you cannot, manually URL-encode the trace ID before calling fetch_trace (e.g., using urllib.parse.quote(trace_id, safe='')) to match the server's expectation. This workaround ensures the API receives the correct encoded identifier.

import urllib.parse
raw_id = '1#3ffe8817'
encoded_id = urllib.parse.quote(raw_id, safe='')
langfuse.fetch_trace(encoded_id)  # Works with encoded ID, not with raw_id

Related patterns

otel_regression_span_processor

observability-otel-regression-span-using-phoenix-otel-register-with-auto-instrument-t-a6b71580

Tier 1 · 70%
tracing_disabling

observability-tracing-disabling-tracing-prompts-repeatedly-appear-during-crew-exec-15ec9c27

Tier 1 · 70%
async_generator_output

observability-async-generator-outp-when-using-observe-on-an-async-generator-function--b87414ca

Tier 1 · 70%
trace_name_overwrite

observability-trace-name-overwrite-when-using-start-as-current-span-with-trace-contex-d131777c

Tier 1 · 70%
version_upgrade_bug

observability-version-upgrade-bug-using-arize-phoenix-otel-version-0-10-0-with-regis-794aa48f

Tier 1 · 70%
streaming_cost_tracking

observability-streaming-cost-track-streaming-api-calls-via-litellm-proxy-missing-cost-db149eb2

Tier 1 · 70%

Have you seen this in your site?

Connect AgentMinds to match against your tech stack automatically.

Run diagnostics