Agent skill

Concave

“Skill: concave”

— description from SKILL.md by udecode

Apache-2.0Auto-check passed

Install Concave

skills CLI

$ npx skills add udecode/kitcn --skill concave -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install udecode/kitcn concave --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/concave .claude/skills/concave && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .claude/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/udecode/kitcn/tree/main/.agents/skills/concave

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add udecode/kitcn --skill concave -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install udecode/kitcn concave --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/concave .agents/skills/concave && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .agents/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add udecode/kitcn --skill concave -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install udecode/kitcn concave --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/concave .cursor/skills/concave && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .cursor/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/udecode/kitcn.git --path .agents/skills/concave

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add udecode/kitcn --skill concave -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install udecode/kitcn concave --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/concave .gemini/skills/concave && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .gemini/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install udecode/kitcn concave

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add udecode/kitcn --skill concave -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/concave .github/skills/concave && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .github/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add udecode/kitcn --skill concave -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install udecode/kitcn concave --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/udecode/kitcn.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/concave .opencode/skills/concave && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "concave" agent skill from https://github.com/udecode/kitcn/tree/main/.agents/skills/concave into .opencode/skills/concave/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "concave", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: concave
GitHub stars: 450
Token cost: ~2.2k tokens
SKILL.md length: 880 words
Files: 1
Skills in repo: 33
Repo updated: Oct 1, 2026
First seen: Oct 7, 2026
Licence: Apache-2.0

At a glance

Works in 6 steps: Re-read current repo wiring → Re-fetch the upstream Concave doc index → Re-fetch every linked page from llms.txt → …
SKILL.md covers Scope, Upstream Concave Facts That…, Current Repo Usage and Repo-Specific Concave…, plus 4 more sections
Calls bun, curl and rg; reaches docs.concave.dev

About this skill

Concave is a skill in udecode/kitcn (450 stars). Its SKILL.md is about 2.2k tokens. Licence: Apache-2.0.

Workflow steps

6 steps, taken from the step headings in SKILL.md.

Re-read current repo wiring
Re-fetch the upstream Concave doc index
Re-fetch every linked page from llms.txt
Rewrite this file with Concave-only facts
Regenerate agent docs
Validate the skill wiring

What it can do on your machine

Read from SKILL.md and the folder at commit c6010f5. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- bun
- curl
- rg
- bunx
From the folder's file list and the shell code blocks in SKILL.md.
Network
Hosts in commands or code, which the agent is likely to contact:
- docs.concave.dev
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Concave loads about 2.2k tokens when it runs. Until then it costs about 6 tokens; SKILL.md has 880 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~6
When it runs · the whole SKILL.md, loaded when a task matches: ~2.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from udecode/kitcn at commit c6010f5, republished under its Apache-2.0 licence (© udecode). 880 words, ~2,179 tokens.

Download SKILL.mdSave it as .claude/skills/concave/SKILL.md (or your agent's skills folder).

name: concave
description: Skill: concave

Concave

Scope

Use this skill for Concave-specific behavior and Concave-vs-Convex differences in this repo.

Use concave-parity when the task is specifically about parity gaps, local workarounds, or removing Concave-specific bandaids after upstream catches up.

Keep the boundary hard:

public kitcn CLI supports backend: "concave" and --backend concave
public kitcn CLI still defaults to Convex
/example stays on Convex
the big convex-test suites stay on Convex tooling
Concave is both a real kitcn backend and the repo's preferred agent/CI runtime lane

Do not restate generic Convex docs here. The convex skill already owns that.

Upstream Concave Facts That Actually Matter

These are the Concave-only facts worth keeping in your head.

Runtime model

Concave is Convex-compatible, self-hosted, and multi-runtime.
Supported runtimes marked production upstream:
- Cloudflare Workers
- Bun
- Node.js
Bun is the default local runtime.
Node.js requires 22.5+ and --experimental-sqlite.
Cloudflare is the recommended production target.

Deployment shape

Cloudflare uses Workers + Durable Objects.
DO SQLite is the default document store on Cloudflare.
D1 is optional when you need different scaling characteristics.
R2 is only needed for ctx.storage.
Self-hosted Bun/Node and desktop embeddings are single-instance by default because SQLite needs exclusive file access.
concave build can compile a standalone Bun-based binary; useful, but still single-instance with SQLite.

Local dev shape

concave dev auto-picks runtime; --bun, --node, and --cf force it.
alpha.14 defaults local dev to 3210.
Bun/Node local data lives in ./.concave/local.
Bun dev binds 0.0.0.0 by default. That is LAN-visible. 127.0.0.1 is the safer local-only bind.
Local dashboard lives at /_dashboard.
DevTools are web-only and designed around Vite/manual client init, not React Native.

Configuration / API differences

concave.config.ts is real Concave surface area.
convex.json works now. That matters here because kitcn already uses it.
Bun/Node use createConcave(...).
Cloudflare uses explicit defineConcaveRuntime(...) wiring.
Adapter choice is part of the product, not hidden infra:
- docstore
- blobstore
- module loading
- Cloudflare bindings

Compatibility gaps

Vector search is only basic/brute-force in built-in adapters.
Crons are planned, not done.
Convex Auth is not supported.
Streaming exports are not supported.

Testing stance upstream

convex-test is still valid for isolated function/unit tests.
Real E2E against Concave is done with createConcave(...) plus ConvexHttpClient.
Cross-runtime E2E is a real supported testing strategy upstream.

Current Repo Usage

We use Concave in two concrete ways.

Public backend selector

kitcn now resolves backend in this order:

--backend <convex|concave>
meta["kitcn"].backend in concave.json
default convex

Public meaning:

convex => drive Convex CLI
concave => drive Concave CLI

Internal meaning:

public concave currently maps to the Bun adapter (concave-bun)

Files:

packages/kitcn/src/cli/config.ts
packages/kitcn/src/cli/core.ts
packages/kitcn/src/cli/cli.ts

Command shape:

kitcn orchestration commands (init, dev, codegen, deploy, migrate, aggregate, reset) run on the selected backend
unknown commands pass through to the selected backend CLI
kitcn env sync stays a kitcn helper
raw kitcn env ... passthrough is Convex-only because Concave has no matching upstream env command

Concave smoke lane

Use:

bash

bun run test:concave

Files:

test/concave/run-smoke.ts
test/concave/fixture/**

Runtime shape:

createConcave(...)
SqliteDocStore(':memory:')
ConvexHttpClient

Goal:

generated kitcn runtime contract loads
one mutation/query roundtrip works end-to-end

Keep it small. This is a smoke lane, not a migration plan.

Repo-Specific Concave Differences

Template sync/check uses the public backend selector

tooling/fixtures.ts runs local committed starter sync with kitcn init -t <next|vite> --backend concave.

That means:

committed fixtures/*/convex/functions/_generated/* comes from the create flow running kitcn codegen against Concave-backed bootstrap
template-mode Concave codegen intentionally uses concave codegen --static
tooling/fixtures.ts itself must not shell out to raw kitcn codegen

Show full SKILL.md (328 more words)Show less

`_generated/*` drift is expected

Concave-generated _generated/* output is not guaranteed to match Convex-generated output byte-for-byte.

Read the diff before calling it a bug.

`staticDataModel` mismatch is still real

Current repo finding:

fixtures/next/convex.json sets codegen.staticDataModel: true
Concave-generated fixtures/next/convex/functions/_generated/dataModel.d.ts is still dynamic

So today, in this repo path, Concave is not honoring that flag.

`api.d.ts` override is gone

Current repo truth:

alpha.14 emits the same api.d.ts shape our old source-backed override used to force
kitcn no longer post-writes _generated/api.d.ts

Meaning:

if api.d.ts drifts again, treat it as a fresh upstream regression
do not quietly resurrect the old overwrite helper

Use plain `bun`, not `bun test`, for the smoke lane

Root bun test preloads Happy DOM here. That poisoned ConvexHttpClient behavior for the Concave smoke lane.

Keep the smoke entry as:

bash

bun ./test/concave/run-smoke.ts

Keep the adapter tiny

Do not invent a second fake runtime layer on top of backend.

The right model is:

one public selector: backend
one internal mapping: concave -> current Bun adapter
native backend flags stay native

Read Before Editing

Start with repo wiring:

packages/kitcn/src/cli/backend-core.ts
packages/kitcn/src/cli/commands/init.ts
packages/kitcn/src/cli/commands/init.test.ts
tooling/fixtures.ts
tooling/fixtures.test.ts
tooling/scenarios.ts
tooling/scenarios.test.ts
test/concave/run-smoke.ts
test/concave/fixture/**
.github/workflows/ci.yml

Then read Concave docs starting from:

https://docs.concave.dev/llms.txt

Do Not

do not add a second selector like --runtime concave
do not switch /example to Concave
do not migrate the big convex-test suites just because Concave exists
do not document generic Convex APIs here
do not assume Concave codegen output equals Convex codegen output

Verification

When touching Concave repo-runtime wiring, run:

bash

bun test packages/kitcn/src/cli/commands/init.test.ts ./tooling/fixtures.test.ts ./tooling/scenarios.test.ts
bun test packages/kitcn/src/cli/cli.test.ts
bun run test:concave
bun run fixtures:check
bun run scenario:check

If package code changed too, also run:

bash

bun --cwd packages/kitcn build
bun lint:fix
bun typecheck

Skill Sync

When Concave docs or repo usage changes, update this skill with this exact loop.

1. Re-read current repo wiring

bash

rg -n "backend|concave-bun|test:concave|createConcave|@concavejs|Concave|--backend" \
  package.json \
  packages/kitcn/src/cli/backend-core.ts \
  packages/kitcn/src/cli/config.ts \
  packages/kitcn/src/cli/cli.ts \
  packages/kitcn/src/cli/commands/init.ts \
  packages/kitcn/src/cli/commands/init.test.ts \
  tooling/fixtures.ts \
  tooling/fixtures.test.ts \
  tooling/scenarios.ts \
  tooling/scenarios.test.ts \
  test/concave \
  .github/workflows/ci.yml \
  -g '!**/_generated/**'

2. Re-fetch the upstream Concave doc index

bash

mkdir -p /tmp/concave-docs-fetch
curl -fsSL -A 'Mozilla/5.0' https://docs.concave.dev/llms.txt \
  | tee /tmp/concave-docs-fetch/llms.txt

3. Re-fetch every linked page from `llms.txt`

bash

awk '
  match($0, /(https:\\/\\/docs\\.concave\\.dev[^) ]+)/, m) { print m[1] }
' /tmp/concave-docs-fetch/llms.txt \
  | nl -ba \
  | while read -r n url; do
      curl -fsSL -A 'Mozilla/5.0' "$url" >"/tmp/concave-docs-fetch/${n}.md"
    done

4. Rewrite this file with Concave-only facts

Rules:

keep only Concave-specific behavior or Concave-vs-Convex differences
keep repo-specific usage and mismatches
do not restate generic Convex docs

5. Regenerate agent docs

bash

bunx skiller@latest apply

6. Validate the skill wiring

bash

bun run intent:validate
bun run intent:stale

If .claude/AGENTS.md changes, that is expected. It is generated from .claude/**.

Files

Just SKILL.md in .agents/skills/concave of udecode/kitcn.

Open the folder on GitHubat commit c6010f5

Compare with similar skills

Concave next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Concave compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Concave this skilludecode/kitcn	450	—	~2.2k	Automated safety check: Pass	Apache-2.0	6 days ago
Durable Objectshodgef/apiker	127	4 repos	~1.5k	Automated safety check: Pass	MIT	1 mo ago
Memoraagentic-box/memora	731	—	~813	Automated safety check: Pass	MIT	9 days ago
Database MigrationRain-kl/OpenFlare	288	—	~1.3k	Automated safety check: Pass	Apache-2.0	today
LogstoreRain-kl/OpenFlare	288	—	~751	Automated safety check: Pass	Apache-2.0	today
Cloudflare D1alinaqi/maggy	707	—	~4.1k	Automated safety check: Pass	MIT	13 days ago

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Questions about Concave

How do I install Concave in Claude Code?

Run `npx skills add udecode/kitcn --skill concave -a claude-code`. Or copy the skill folder (.agents/skills/concave in udecode/kitcn) into .claude/skills/concave in your project. Claude Code loads it when a task matches its description.

How do I install Concave in Codex?

Run `npx skills add udecode/kitcn --skill concave -a codex`. Or copy the skill folder (.agents/skills/concave in udecode/kitcn) into .agents/skills/concave in your project. Codex loads it when a task matches its description.

Can I use Concave in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add udecode/kitcn --skill concave -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/concave, .gemini/skills/concave, .github/skills/concave and .opencode/skills/concave in your project.

What does Concave need to run?

Going by SKILL.md and its folder, Concave needs the command-line tools its instructions call (bun, curl, rg and bunx).

Does Concave access the network?

SKILL.md names 1 domain. In commands or code: docs.concave.dev; the agent is likely to contact it when it follows the instructions. This is read from the text; nothing was executed.

Is Concave safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Concave use?

Concave is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Concave use?

About 2.2k tokens (SKILL.md is roughly 8.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Concave?

Skills that share tags, products or a category with Concave: Durable Objects (hodgef/apiker, 127 stars), Memora (agentic-box/memora, 731 stars), Database Migration (Rain-kl/OpenFlare, 288 stars) and Logstore (Rain-kl/OpenFlare, 288 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Concave?

udecode (a GitHub organization) maintains it in udecode/kitcn, which has 450 GitHub stars. The repository holds 33 skills in this directory. The repository was last updated on October 1, 2026.

Source: udecode/kitcn on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Concave

Facts

At a glance

About this skill

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Concave

Scope

Upstream Concave Facts That Actually Matter

Runtime model

Deployment shape

Local dev shape

Configuration / API differences

Compatibility gaps

Testing stance upstream

Current Repo Usage

Public backend selector

Concave smoke lane

Repo-Specific Concave Differences

Template sync/check uses the public backend selector

_generated/* drift is expected

staticDataModel mismatch is still real

api.d.ts override is gone

Use plain bun, not bun test, for the smoke lane

Keep the adapter tiny

Read Before Editing

Do Not

Verification

Skill Sync

1. Re-read current repo wiring

2. Re-fetch the upstream Concave doc index

3. Re-fetch every linked page from llms.txt

4. Rewrite this file with Concave-only facts

5. Regenerate agent docs

6. Validate the skill wiring

Files

Compare with similar skills

Similar skills

More from udecode/kitcn

Related

Questions about Concave

`_generated/*` drift is expected

`staticDataModel` mismatch is still real

`api.d.ts` override is gone

Use plain `bun`, not `bun test`, for the smoke lane

3. Re-fetch every linked page from `llms.txt`