tengu_prompt_cache_diagnosis_received
A Claude Code feature flag, read out of the shipped bundle. No mined inventory carries it: everything below comes from what this site has written about it.
MCP server error lines are escaped before display, plus minor telemetry and version-string cleanups.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.219.
In the changelogs
2Releases whose published page names tengu_prompt_cache_diagnosis_received.
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v2.1.265
Prompt cache diagnosis telemetry now allowlists diagnosisType values
Prompt-cache diagnosis telemetry now only sends recognized diagnosis types, replacing others with 'other'
gate cited by this entry, found in this entry's text
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v2.1.219
MCP error escaping, typed telemetry ids and shared version normalisation
MCP server error lines are escaped before display, plus minor telemetry and version-string cleanups.
gate cited by this entry, found in this entry's text
Gate readings
0No release here has a gate table behind it for this flag. Most published releases have none at all: the readings exist only for versions the pipeline captured flag state on.
First cited
1The earliest release whose published evidence quoted tengu_prompt_cache_diagnosis_received was v2.1.219, 24 Jul 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the feature flag does. All feature flags.