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Durable Objects · fcakyon | DecimalAI

codingby fcakyon

Durable Objects

fcakyon/durable-objects

Source fcakyon/claude-codex-settings ↗License Apache-2.0

Build, debug, or review Cloudflare Durable Objects code for persistent state and coordination.

SkillScore86Maintained

Automatic

Coding pack

Last verified 10/10/2026

What it changes

Passed 19 of 22 test cases with the skill, and 13 of 22 without it.

Without skill59%

With skill86%

Checks it passed that the model alone missed

Uses new_sqlite_classes in the migration block of wrangler.jsonc
Calls toArray on the SQL execution result to return matching rows
Uses getByName with the room identifier to resolve the instance stub

and 3 more in the full report

6 fixed13 passed either way3 still failing0 broke

Pass-rate lift: +27 pp
Tokens: +49%
Agent turns: 0%
Response time: -16%

Model gemini-3.6-flashMeasured 10/10/2026v219 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/fcakyon-durable-objects/SKILL.md https://app.decimal.ai/s/fcakyon-durable-objects/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add fcakyon-durable-objects, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/fcakyon-durable-objects/ and pins it in .decimal/skills.lock

decimalai skills add fcakyon-durable-objects

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/fcakyon-durable-objects/SKILL.md https://app.decimal.ai/s/fcakyon-durable-objects/SKILL.md

Raw file: /s/fcakyon-durable-objects/SKILL.md ↗ · machine-readable summary at /s/fcakyon-durable-objects.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 6

Prompt

We are configuring wrangler.jsonc for a new project that uses Durable Object RPC method calls directly on stubs. What is the minimum compatibility_date setting required in wrangler.jsonc for Durable Object RPC support?

What was checked, without and with the skill
Checked	Without skill	With skill
Sets the compatibility_date field in wrangler.jsonc to 2024-04-03 or later	Missed	Passed

case-16 · gemini-3.6-flash · 10/10/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md175 lines4 files

Durable Objects

Build stateful, coordinated applications on Cloudflare's edge using Durable Objects.

Retrieval Sources

Your knowledge of Durable Objects APIs and configuration may be outdated. Prefer retrieval over pre-training for any Durable Objects task.

Resource	URL
Docs	https://developers.cloudflare.com/durable-objects/index.md
API Reference	https://developers.cloudflare.com/durable-objects/api/index.md
Best Practices	https://developers.cloudflare.com/durable-objects/best-practices/index.md
Examples	https://developers.cloudflare.com/durable-objects/examples/index.md
Roles and permissions	https://developers.cloudflare.com/workers/authorization/durable-objects/index.md

Fetch the relevant doc page when implementing features.

When to Use

Creating new Durable Object classes for stateful coordination
Implementing RPC methods, alarms, or WebSocket handlers
Reviewing existing DO code for best practices
Configuring wrangler.jsonc/toml for DO bindings and migrations
Writing tests with Cloudflare’s Vitest integration
Designing sharding strategies and parent-child relationships

Reference Documentation

./references/rules.md - Core rules, storage, concurrency, RPC, alarms
Testing reference - Current Vitest documentation, migration choices, and test selection
./references/workers.md - Workers handlers, types, wrangler config, observability

Search: blockConcurrencyWhile, idFromName, getByName, setAlarm, sql.exec

Core Principles

Use Durable Objects For

| Need | Example |

Track record

Benchmark

19 / 22

test cases passed, vs 13 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v5 — 10/9/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

fcakyon / claude-codex-settings

plugins/cloudflare-skills/skills/durable-objects/SKILL.md

View on GitHub ↗

License Apache-2.0Imported 10/9/2026Version v2Bundled 3 files

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Ready to supercharge your AI agents?

See it in action

What's inside

Durable Objects

Retrieval Sources

When to Use

Reference Documentation

Core Principles

Use Durable Objects For

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

Related skills