turso: Skill for Claude Code

.claude/skills/debugging/SKILL.md

debugging is a skill for Claude Code from tursodatabase/turso. It costs 28 tokens per session (777 once invoked), scanned A, original, MIT.

A guide for debugging TursoDB, a database compatible with SQLite. It describes comparing internal query instructions, collecting logs, finding threading problems, reproducing bugs with fixed seeds, and investigating corruption.

In plain words
What is it for?
Use it to inspect SQL and query plans, compare TursoDB with SQLite, run traced tests, use ThreadSanitizer, reproduce deterministic simulations, and analyze database failures.
Why use it?
It gives you a repeatable way to determine whether a database bug comes from query generation, execution, storage, concurrency, or corrupted data.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is tursodatabase/turso's own configuration. It tells Claude Code how to work on turso itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything turso configures →

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is SEED=1234 ./testing/concurrent-simulator/bin/run.

About the project

Turso is an in-process SQL database written in Rust that is compatible with SQLite and also accepts PostgreSQL syntax through an experimental frontend. It is for applications and organizations that need an embeddable database engine with support for multiple languages, platforms, and database features. The catalogue entries are skills and instructions for working with Turso.

tursodatabase/turso · 25,079 stars · on GitHub

Reuse

Borrowing it

Nothing to install: this file belongs to tursodatabase/turso. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tursodatabase/turso/main/.claude/skills/debugging/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tursodatabase/turso

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for debugging

README.md
[![agentmods](https://agentmods.dev/badge/skills/tursodatabase/turso/debugging/github.svg)](https://agentmods.dev/skills/tursodatabase/turso/debugging)
Your own site
<a href="https://agentmods.dev/skills/tursodatabase/turso/debugging"><img src="https://agentmods.dev/badge/skills/tursodatabase/turso/debugging/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for debugging

Your own site · 80×15
<a href="https://agentmods.dev/skills/tursodatabase/turso/debugging"><img src="https://agentmods.dev/badge/skills/tursodatabase/turso/debugging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 777 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 5 Oct 2026
  • Snyk pass 14 Sept 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00028 $0.00777
Opus 5.5 $0.00011 $0.00311
Sonnet 5.5 $0.00006 $0.00155
Haiku 4.5 $0.00003 $0.00078

Measured 23d ago against content hash a004c7b481e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

debugging scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 23d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/debugging/SKILL.md · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debugging Guide

Bytecode Comparison Flow

Turso aims for SQLite compatibility. When behavior differs:

1. EXPLAIN query in sqlite3
2. EXPLAIN query in tursodb
3. Compare bytecode
   ├─ Different → bug in code generation
   └─ Same but results differ → bug in VM or storage layer

Example

# SQLite
sqlite3 :memory: "EXPLAIN SELECT 1 + 1;"

# Turso
cargo run --bin tursodb :memory: "EXPLAIN SELECT 1 + 1;"

Manual Query Inspection

cargo run --bin tursodb :memory: 'SELECT * FROM foo;'
cargo run --bin tursodb :memory: 'EXPLAIN SELECT * FROM foo;'

Logging

# Trace core during tests
RUST_LOG=none,turso_core=trace make test

# Output goes to testing/test.log
# Warning: can be megabytes per test run

Threading Issues

Use stress tests with ThreadSanitizer:

rustup toolchain install nightly
rustup override set nightly
cargo run -Zbuild-std --target x86_64-unknown-linux-gnu \
  -p turso_stress -- --vfs syscall --nr-threads 4 --nr-iterations 1000

Deterministic Simulation

Reproduce bugs with seed. Note: simulator uses legacy "limbo" naming.

# Simulator
RUST_LOG=limbo_sim=debug cargo run --bin limbo_sim -- -s <seed>

# Whopper (concurrent DST)
SEED=1234 ./testing/concurrent-simulator/bin/run

Stack Usage

Parsing and translating an expression recurse once per level of nesting, so the stack frame size of those functions limits how deep an expression can be. Three scripts in scripts/stack/ measure stack use. Use a release build (cargo build --release --bin tursodb): debug builds do not reuse stack slots, so their frames say little about what users run. Run each script with -h for all options.

# Frame size of each function, read from its prologue. -c compares two binaries.
scripts/stack/frame-sizes.sh 'translate::expr::'
scripts/stack/frame-sizes.sh -c /tmp/tursodb-main 'translate_expr$' 'parse_expr_inner$'

# Smallest stack that runs a SQL script, per binary. -S adds sqlite3.
scripts/stack/min-stack.sh -S -b /tmp/tursodb-main -b target/release/tursodb deep.sql

# Which functions use the stack at the deepest point (runs under lldb).
scripts/stack/stack-profile.sh deep.sql

Read the full file on GitHub · 105 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 23d ago Changed · +24 lines a004c7b481e1
  2. 1mo ago First seen · 81 lines · 28 tokens per session scan A 8a94146144a2

Subscribe to this mod's changes

debugging is a skill published in the GitHub repository tursodatabase/turso (25,079 stars, last pushed today), licensed MIT. It adds 28 tokens to every session and 777 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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