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Sweep 28 Aug 2026 · 00:00Z Build v2.1.250 478 read Stable v2.1.236 Latest v2.1.250 Next v2.1.250 Feeds RSS JSON llms.txt

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

Reference / Environment variables

CLAUDE_CODE_OTEL_HEADERS_HELPER_DEBOUNCE_MS

A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.

What it is

Interval for refreshing dynamic OpenTelemetry headers in milliseconds (default: 1740000 / 29 minutes). See [Dynamic headers](/docs/en/monitoring-usage#dynamic-headers)

Anthropic's own wording. Read off Environment variables, captured 2026-08-28.

Presence across releases

ReleasesReadingDeclared typeDefault
2.1.245 – 2.1.250 5 releases never mined — —
2.1.160 – 2.1.243 75 releases in the build int —
2.1.138 – 2.1.159 20 releases in the build — —

A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.

Changelog entries naming it

No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.138 without anybody writing a line about it.

Documentation pages

A reference table page is one whose own table defines this name, and it is where the description above came from. A page that mentions it carries the name somewhere in its text and may say nothing about it at all. Every page carrying it.

Names beside it

Every environment variable in the inventory starting claude_code_otel, up to twelve of them.

CLAUDE_CODE_OTEL_CONTENT_MAX_LENGTHMaximum length of content-bearing OpenTelemetry attributes (model responses, tool content, system prompts, raw API bodies), truncation marker included, in UTF-16 code units (default: 61440, i.e. 60 KB). Raise it only if your telemetry backend accepts attribute values larger than 64 KB, or lower it to cut telemetry volume. Requires Claude Code v2.1.214 or later. See [Monitoring](/docs/en/monitoring-usage) 2.1.213 CLAUDE_CODE_OTEL_DIAG_STDERRSet to 1 to write OpenTelemetry exporter diagnostic errors to stderr. By default these errors only appear with --debug, so a misconfigured exporter such as a Prometheus port collision otherwise fails silently. Requires Claude Code v2.1.179 or later. See [Monitoring](/docs/en/monitoring-usage) 2.1.179 CLAUDE_CODE_OTEL_FLUSH_TIMEOUT_MSTimeout in milliseconds for flushing pending OpenTelemetry spans (default: 5000). See [Monitoring](/docs/en/monitoring-usage) 2.1.138 CLAUDE_CODE_OTEL_SHUTDOWN_TIMEOUT_MSTimeout in milliseconds for the OpenTelemetry exporter to finish on shutdown (default: 2000). Increase if metrics are dropped at exit. See [Monitoring](/docs/en/monitoring-usage) 2.1.138

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 environment variable does. All environment variables.