Backend & API Design Good First Issues

Browse open source issues grouped under Backend & API Design. Where the subject goes by older names in the issue metadata, those are matched too.

Backend & API Design

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Average annotated difficulty: 3.6/5 across 9,868 issues.
13% of 9,868 time estimates are one day or less.

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[BUG] No Connection Open

area:claude-code-web bug duplicate platform:web

anthropics/claude-code#93167 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] MCP tool calls with dict/array parameters serialized as strings, fails mid-session after working correctly Open

area:mcp bug platform:macos

anthropics/claude-code#93179 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Workflow script API: no way to continue a previously spawned agent Open

area:agents enhancement

anthropics/claude-code#93202 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Repeated API errors require multiple correction attempts Open

area:model bug needs-repro platform:macos

anthropics/claude-code#93214 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Usage/rate-limit page gives no explanation when a session is blocked Open

invalid

anthropics/claude-code#93240 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] archive_session refuses a pinned session, and the refusal can't say which of four conditions blocked it Open

area:desktop area:mcp bug has repro platform:macos

anthropics/claude-code#93259 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Projects: concurrent sessions silently clobber each other's project_write — three losses on one doc in ninety minutes Open

area:agents area:tools bug data-loss

anthropics/claude-code#93260 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Artifact db capability: reads/writes silently fail (no data persists) across networks, browsers, devices Open

area:claude-code-web bug platform:web

anthropics/claude-code#93261 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
claude.ai Gmail MCP create_draft: the google.com/url wrapper is emitted CORRUPTED (raw 0x17 in place of "=1"), and the substituted signature carries no gmail_signature marker Open

area:cowork area:mcp bug platform:web

anthropics/claude-code#93271 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Anthropic API Error: Incorrect [cyber] Flag Classification for Authorized Security Assessment Open

area:model area:security bug duplicate platform:linux

anthropics/claude-code#93272 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Windows 2.1.267: session state becomes inconsistent after auto-compaction (false continuation, missing attachments, stale sessions appear recent) Open

api:anthropic area:core bug has repro platform:windows

anthropics/claude-code#93277 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Claude Desktop / Claude Code CLI send Mcp-Protocol-Version: 2025-11-25 with _meta protocolVersion 2026-07-28 via claude.ai connectors — spec-compliant stateless servers reject every call (-32020 header mismatch) Open

area:mcp bug has repro platform:macos

anthropics/claude-code#93290 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] `DISABLE_PROMPT_CACHING_HAIKU` is silently ignored when Haiku is the main model — undocumented main-model guard, absent on `_SONNET`/`_OPUS` Open

area:core bug has repro platform:macos

anthropics/claude-code#93295 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] hangs indefinitely Open

area:mcp area:permissions area:routines bug has repro platform:web

anthropics/claude-code#93304 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Code sessions don't sync to mobile Remote Control (chat/cowork do) Open

area:cowork bug

anthropics/claude-code#93305 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Desktop: BYO OAuth MCP connect fails with malformed "Issuer mismatch (RFC 8414 §3.3)" error — same version-negotiation probe as #87713 Open

area:auth area:desktop area:mcp bug has repro platform:macos platform:windows regression

anthropics/claude-code#93327 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Anthropic API Error: Safeguard False Positive on Legitimate Code Task Open

area:model bug needs-repro platform:intellij platform:macos

anthropics/claude-code#93335 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] [SHOW-STOPPER] Usage Credits suddenly being ignored by Claude Code Terminal Open

api:anthropic area:cost bug platform:windows

anthropics/claude-code#93344 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Remote Control: session worktrees are deleted before the session is archived, and activeSessionIds is almost never persisted Open

area:core bug has repro platform:linux

anthropics/claude-code#93345 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Channels: allow an image param on notifications/claude/channel Open

area:plugins enhancement

anthropics/claude-code#93361 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Rotinas geradas não se conectam no remoto Open

area:desktop area:routines bug platform:windows

anthropics/claude-code#93370 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Usage tracking incorrectly associated with unrelated chat context Open

area:cost question

anthropics/claude-code#93380 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[FEATURE] Bound background Bash tasks: optional deadline + surface output staleness in the Background tasks panel Open

area:bash area:tui enhancement platform:macos

anthropics/claude-code#93387 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Failed to establish connection to Notion API Open

area:auth area:mcp bug platform:linux

anthropics/claude-code#93412 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Workflow tool's StructuredOutput validator false-rejects valid output ("missing required property" when property is present) Open

area:agents area:routines duplicate

anthropics/claude-code#93430 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Expensive API calls due to missing conversation memory in Claude Code Open

area:tui bug duplicate platform:windows

anthropics/claude-code#93434 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Anthropic API Error: Opus 5 safety filter blocks legitimate coding tasks Open

api:anthropic area:model bug duplicate platform:macos

anthropics/claude-code#93467 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Claude in Chrome: a page still in its loading skeleton and a genuinely empty page return the same successful no-match result to read_page, find and javascript_tool Open

area:chrome enhancement platform:macos

anthropics/claude-code#93472 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Claude in Chrome extension: CLI session reports "not connected" indefinitely, even with a fresh native-messaging host, no competing sessions, and the extension showing enabled/connected on the Chrome side Open

area:chrome bug has repro platform:macos

anthropics/claude-code#93473 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Cowork: device_commit_files reports success on overwrites but the on-disk content lags exactly one commit behind (silent stale write, fresh mtime) Open

area:cowork bug data-loss has repro platform:windows

anthropics/claude-code#93482 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] --resume never hits the prompt cache past the static prefix on Fable 5.1 (opus hits): session-start context message is replayed as a plain string instead of the content blocks it was sent with Open

area:core area:cost bug has repro performance platform:macos

anthropics/claude-code#93490 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] False positive validation error on legitimate API requests Open

area:api bug needs-info platform:linux

anthropics/claude-code#93504 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Constant 'API Error / Disconnected / Retry x of 10' on 2.1.268 (macOS 26.2) — auto-mode classifier also timing out Open

area:networking bug platform:macos

anthropics/claude-code#93509 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Cowork VM egress allowlist ignores Admin Capabilities network access settings Open

area:cowork area:networking bug duplicate

anthropics/claude-code#93520 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Anthropic API Error: Overly aggressive safety filtering on legitimate system signal operations Open

api:anthropic area:model area:security bug duplicate platform:linux

anthropics/claude-code#93524 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] MessageDisplay no longer fires for text between tool calls (regression) Open

area:hooks bug has repro platform:vscode platform:windows regression

anthropics/claude-code#93531 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Opus 5 safeguards false-positive on legitimate bacterial genomics research (`[bio]` flag) Open

area:model bug platform:windows platform:wsl

anthropics/claude-code#93533 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
remote-control: routine sessions are never sent end_session on completion, and when it is sent the harness exits non-zero Open

area:routines bug has repro platform:macos

anthropics/claude-code#93549 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] Anthropic API Error: Sonnet 5 Cyber Safeguards Flagging Legitimate Requests Open

api:anthropic area:model area:security bug duplicate platform:linux

anthropics/claude-code#93550 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Weekly limits reset when switching machines Open

area:cost bug

anthropics/claude-code#93551 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
No way to see which routine sessions are still alive and holding resources Open

area:routines area:ui enhancement

anthropics/claude-code#93552 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Cloud-run Cowork scheduled task fires on time, then stalls mid-run at the first turn boundary Open

area:cowork bug

anthropics/claude-code#93556 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Auto-mode classifier attribution repair misses custom gateway base URLs (follow-up to #64585) Open

api:anthropic area:permissions bug has repro

anthropics/claude-code#93558 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Egress allowlist ignores "All domains": every host outside a built-in list gets 403 on CONNECT (regression 2026-09-10 -> 2026-09-11) Open

area:cowork area:networking area:routines bug regression

anthropics/claude-code#93562 · 8 comments · 6 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Claude Desktop – "Configure third-party inference" setup page fails with 503 (bootstrap request) Closed

invalid

anthropics/claude-code#93577 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
You've hit your session limit · resets 1:30pm (Europe/Prague) Open

area:cost bug platform:windows

anthropics/claude-code#93579 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[BUG] Plugin HTTP MCP ${VAR} header expansion resolves to empty in 2.1.260 (works in 2.1.247 / 2.1.223) — bearer token never sent Open

area:mcp area:plugins bug has repro platform:windows regression

anthropics/claude-code#93595 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[FEATURE] Support multiple simultaneous Notion workspace connections in one session Open

area:mcp duplicate

anthropics/claude-code#93606 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
Channel messages are merged into the previous user message and re-rendered on the next request, losing the prompt cache on non-Anthropic backends Open

area:cost area:plugins bug platform:wsl

anthropics/claude-code#93622 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026
[Bug] macOS: teammate spawn "fork failed: Device not configured" — xnu ptmx slot-vector race triggered by cat placeholder + respawn-pane -k (root cause for #77211) Open

area:agents bug has repro platform:macos

anthropics/claude-code#93624 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 14, 2026

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Backend & API Design Good First Issues

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