An entry is only as true as the day it was written.
Flags move on the server after a release ships. Anthropic's own notes land days later and their documentation later still. Sometimes an entry turns out to be wrong and gets corrected by hand. All of that is recorded against the entry it happened to, and this is the whole of it in the order it happened.
Nothing here replaces an entry. Every line links to the page its release published, still saying what that release said, because a correction is added and dated rather than swapped in.
| When | Entry | What happened |
|---|---|---|
v2.1.293haiku |
Documentation arrivedA small documentation edit on overview touched a line naming haiku after this was published.
the line in the docs* Code written for Claude Haiku 4.5 can break on Claude Haiku 5.5. Manual extended thinking (`budget_tokens`), the sampling parameters `temperature`, `top_p`, and `top_k`, and assistant message prefill can each return a 400 error. `compute… |
|
v2.1.288output_config.format |
Documentation arrivedAnthropic's documentation has since written up output_config.format, on migration-guide.
the line in the docs11. If you use [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs) (`output_config.format` or `strict: true` tools) on Amazon Bedrock, describe the format in the prompt or use a tool without `stri… |
|
v2.1.293SessionEnd |
Documentation arrivedAnthropic's documentation has since written up SessionEnd, on events-and-streaming.
the line in the docs&& idle.StopReason?.Value is BetaManagedAgentsSessionEndTurn) |
|
v2.1.271multiplier |
Documentation arrivedA small documentation edit on data-residency touched a line naming multiplier after this was published.
the line in the docs* **Claude 4.6 and later models:** US-only inference (`inference_geo: "us"`) is priced at 1.1x the standard rate across all token pricing categories (input tokens, output tokens, cache writes, and cache reads). On Claude Haiku 5.5, the mul… |
|
v2.1.275maxTokens |
Documentation arrivedA small documentation edit on java touched a line naming maxTokens after this was published.
the line in the docsAvoid setting a large `maxTokens` value without using streaming. Some networks may drop idle connections after a certain period of time, which can cause the request to fail or [time out](https://platform.claude.com/docs/en/cli-sdks-librari… |
|
v2.1.293/compact |
Documentation arrivedAnthropic's documentation has since written up /compact, on thinking-troubleshooting.
the line in the docsTo fix it, keep the history append-only: pass earlier turns back exactly as sent and received, add instructions with a [mid-conversation system message](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages… |
|
v2.1.288requestTimeout |
Documentation arrivedAnthropic's documentation has since written up requestTimeout, on mid-conversation-effort-example.
the line in the docsctx, cancel := context.WithTimeout(ctx, requestTimeoutSeconds*time.Second) |
|
v2.1.288requestTimeout |
Documentation arrivedAnthropic's documentation has since written up requestTimeout, on mid-conversation-effort-example.
the line in the docsctx, cancel := context.WithTimeout(ctx, requestTimeoutSeconds*time.Second) |
|
v2.1.293claude-haiku-5-5 |
Documentation arrivedAnthropic's documentation has since written up claude-haiku-5-5, on effort.
the line in the docsClaude Haiku 5.5 supports all five effort levels, and `medium` is the default. Effort is the main control for how much the model thinks, and with it quality, latency, and cost. **Start with `medium`** for most work, including agentic codin… |
|
v2.1.293claude-haiku-5-5 |
Documentation arrivedAnthropic's documentation has since written up claude-haiku-5-5, on effort.
the line in the docsClaude Haiku 5.5 supports all five effort levels, and `medium` is the default. Effort is the main control for how much the model thinks, and with it quality, latency, and cost. **Start with `medium`** for most work, including agentic codin… |
|
v2.1.293claude-haiku-5-5 |
Documentation arrivedAnthropic's documentation has since written up claude-haiku-5-5, on effort.
the line in the docsClaude Haiku 5.5 supports all five effort levels, and `medium` is the default. Effort is the main control for how much the model thinks, and with it quality, latency, and cost. **Start with `medium`** for most work, including agentic codin… |
|
v2.1.293claude-haiku-5-5 |
Documentation arrivedAnthropic's documentation has since written up claude-haiku-5-5, on effort.
the line in the docsClaude Haiku 5.5 supports all five effort levels, and `medium` is the default. Effort is the main control for how much the model thinks, and with it quality, latency, and cost. **Start with `medium`** for most work, including agentic codin… |
|
v2.1.293/compact |
Documentation arrivedA small documentation edit on compaction-on-demand touched a line naming /compact after this was published.
the line in the docs* **Mid-conversation system messages and tool changes.** `role: "system"` messages inside the summarized range are summarized too, so their text instructions stop applying once the block replaces them. A [per-message effort](https://platfo… |
|
v2.1.288claude update |
Documentation arrivedA small documentation edit on claude-in-amazon-bedrock touched a line naming claude update after this was published.
the line in the docsUse Claude Code 2.1.255 or later with Claude Fable 5.1 on Amazon Bedrock, and 2.1.280 or later with Claude Opus 5.5 and Claude Haiku 5.5; run `claude update` to upgrade. |
|
v2.1.290PreToolUse |
Documentation arrivedA small documentation edit on Code in Claude Desktop on 3P touched a line naming PreToolUse after this was published.
the line in the docs| `builtinToolPolicy` | Tools set to `"ask"` require approval on each call in Code sessions, enforced via a PreToolUse hook and Claude Code `permissions.ask` rules. Argument-scoped rules such as `Bash(curl *)` are [applied as managed polic… |
|
v2.1.289PreToolUse |
Documentation arrivedA small documentation edit on Code in Claude Desktop on 3P touched a line naming PreToolUse after this was published.
the line in the docs| `builtinToolPolicy` | Tools set to `"ask"` require approval on each call in Code sessions, enforced via a PreToolUse hook and Claude Code `permissions.ask` rules. Argument-scoped rules such as `Bash(curl *)` are [applied as managed polic… |
|
v2.1.282permissions.ask |
Documentation arrivedA small documentation edit on Code in Claude Desktop on 3P touched a line naming permissions.ask after this was published.
the line in the docs| `builtinToolPolicy` | Tools set to `"ask"` require approval on each call in Code sessions, enforced via a PreToolUse hook and Claude Code `permissions.ask` rules. Argument-scoped rules such as `Bash(curl *)` are [applied as managed polic… |
|
v2.1.281builtinToolPolicy |
Documentation arrivedA small documentation edit on Code in Claude Desktop on 3P touched a line naming builtinToolPolicy after this was published.
the line in the docs| `builtinToolPolicy` | Tools set to `"ask"` require approval on each call in Code sessions, enforced via a PreToolUse hook and Claude Code `permissions.ask` rules. Argument-scoped rules such as `Bash(curl *)` are [applied as managed polic… |
|
v2.1.281disallowedTools |
Documentation arrivedA small documentation edit on Create custom subagents touched a line naming disallowedTools after this was published.
the line in the docsThe full content of each listed skill is injected into the subagent's context at startup, up to the first 32 distinct names in the list. This field controls which skills are preloaded, not which skills the subagent can access: without it, … |
|
v2.1.281disallowedTools |
Documentation arrivedA small documentation edit on Create custom subagents touched a line naming disallowedTools after this was published.
the line in the docsThe full content of each listed skill is injected into the subagent's context at startup, up to the first 32 distinct names in the list. This field controls which skills are preloaded, not which skills the subagent can access: without it, … |
|
v2.1.281disallowedTools |
Documentation arrivedA small documentation edit on Create custom subagents touched a line naming disallowedTools after this was published.
the line in the docsThe full content of each listed skill is injected into the subagent's context at startup, up to the first 32 distinct names in the list. This field controls which skills are preloaded, not which skills the subagent can access: without it, … |
|
v2.1.281disallowedTools |
Documentation arrivedA small documentation edit on Create custom subagents touched a line naming disallowedTools after this was published.
the line in the docsThe full content of each listed skill is injected into the subagent's context at startup, up to the first 32 distinct names in the list. This field controls which skills are preloaded, not which skills the subagent can access: without it, … |
|
v2.1.290claude attach |
Documentation arrivedAnthropic's documentation has since written up claude attach, on Manage multiple agents with agent view.
the line in the docs* `claude attach` prints `This session has no saved transcript`. |
|
v2.1.285API_TIMEOUT_MS |
Documentation arrivedA small documentation edit on Agent SDK reference - Python touched a line naming API_TIMEOUT_MS after this was published.
the line in the docs* `CLAUDE_CODE_MAX_RETRIES`: maximum API retries. Default `10`, capped at `15`. Each retry gets its own `API_TIMEOUT_MS` window. |
|
v2.1.206tengu_umber_kestrel |
Flag reading movedThe flag server now returns on for tengu_umber_kestrel, read as this account. | |
v2.1.239tengu_toasty_breeze |
Flag reading movedThe flag server now returns {"allowanceNote":"{percent} allowance left","budgetExhaustedCopy":"You've used this week's lower-priority allowance","cooloffMinutes":10,"enabled":true,"label":"Continue now at lower priority","noticeLine":"/low-priority to continue now at lower priority · uses your weekly limit","statusLine":"Lower priority until {reset}","version":3,"waitBanner":"Working at lower priority · waiting for capacity"} for tengu_toasty_breeze, read as this account. | |
v2.1.239tengu_toasty_breeze |
Flag reading movedThe flag server now returns {"allowanceNote":"{percent} allowance left","budgetExhaustedCopy":"You've used this week's lower-priority allowance","cooloffMinutes":10,"enabled":true,"label":"Continue now at lower priority","noticeLine":"/low-priority to continue now at lower priority · uses your weekly limit","statusLine":"Lower priority until {reset}","version":3,"waitBanner":"Working at lower priority · waiting for capacity"} for tengu_toasty_breeze, read as this account. | |
v2.1.282tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.281tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.281tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.269tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.261tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.261tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns on for tengu_smooth_chipmunk, read as this account. | |
v2.1.273tengu_quiet_dolphin |
Flag reading movedThe flag server now returns on for tengu_quiet_dolphin, read as this account. | |
v2.1.248tengu_nifty_lemur |
Flag reading movedThe flag server now returns {"autoContinue":true,"enabled":true,"label":"Reset your session limit now","noticeLine":"/limit-reset to reset your session limit now · uses weekly limit · 1/week","spentLine":"Weekly reset used · available again {date}","successLine":"Session limit reset · next reset available {date} · your weekly limit still applies","unavailableLine":"Couldn't reset your session limit right now · try again in a moment","version":1} for tengu_nifty_lemur, read as this account. | |
v2.1.248tengu_nifty_lemur |
Flag reading movedThe flag server now returns {"autoContinue":true,"enabled":true,"label":"Reset your session limit now","noticeLine":"/limit-reset to reset your session limit now · uses weekly limit · 1/week","spentLine":"Weekly reset used · available again {date}","successLine":"Session limit reset · next reset available {date} · your weekly limit still applies","unavailableLine":"Couldn't reset your session limit right now · try again in a moment","version":1} for tengu_nifty_lemur, read as this account. | |
v2.1.284tengu_lantern_wick_text |
Flag reading movedThe flag server now returns "Usage limit reached; a short grace allowance remains, then this turn is cut off without warning. Judge what's left: if it's genuinely only a few steps, finish it properly, then stop and say so without extra polishing. Otherwise don't attempt it all: finish the piece in hand and at most two more like it, then stop. The allowance also pays for any subagents you have running: they don't get this message and will keep going, so it's up to you how to handle them. Either way, end by telling the user their usage limit was reached, what's done and what's left." for tengu_lantern_wick_text, read as this account. | |
v2.1.223tengu_juniper_relay |
Flag reading movedThe flag server now returns on for tengu_juniper_relay, read as this account. | |
v2.1.251tengu_juniper_relay |
Flag reading movedThe flag server now returns on for tengu_juniper_relay, read as this account. | |
v2.1.265tengu_curious_tower_stateless_models |
Flag reading movedThe flag server now returns "" for tengu_curious_tower_stateless_models, read as this account. | |
v2.1.206tengu_umber_kestrel |
Flag reading movedThe flag server now returns off for tengu_umber_kestrel, read as this account. | |
v2.1.239tengu_toasty_breeze |
Flag reading movedThe flag server now returns {"enabled":false,"version":0} for tengu_toasty_breeze, read as this account. | |
v2.1.239tengu_toasty_breeze |
Flag reading movedThe flag server now returns {"enabled":false,"version":0} for tengu_toasty_breeze, read as this account. | |
v2.1.282tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.281tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.281tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.269tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.261tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.261tengu_smooth_chipmunk |
Flag reading movedThe flag server now returns off for tengu_smooth_chipmunk, read as this account. | |
v2.1.273tengu_quiet_dolphin |
Flag reading movedThe flag server now returns off for tengu_quiet_dolphin, read as this account. |