How do I install the TOML skill?

Run npx skillmds add modbender/toml in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the TOML skill do?

Write valid TOML configuration files with correct types and structure. It is listed under Coding & Dev Tools on SkillMD.

This skill has not completed SkillMD's automated safety review yet. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with TOML?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

modbender (@modbender) published this skill. Their other Agent Skills are listed on their SkillMD profile.

TOML by modbender — Agent Skill

Name: TOML
Rating: 4.2 (5 reviews)
Author: modbender

File contents

Strings

Basic strings "..." support escapes: \n, \t, \\, \"
Literal strings '...' are raw—no escape sequences, backslash is literal
Multiline basic """...""" allows newlines; leading newline after """ is trimmed
Multiline literal '''...''' for raw blocks; no escape processing

Keys

Bare keys: alphanumeric, dash, underscore only—key-name_1 valid
Quoted keys for special chars: "key with spaces" or 'key.with.dots'
Dotted keys a.b.c = 1 equivalent to nested tables—defines [a.b] implicitly
Keys are case-sensitive—Key and key are different

Tables

[table] defines table; all following key-values belong to it until next header
[a.b.c] creates nested structure—parent tables created implicitly
Dotted keys under [table] extend it: [fruit] then apple.color = "red" works
Defining table after dotted key created it is error—order matters

Arrays of Tables

[[array]] appends new table to array each time it appears
[[products]] twice creates products[0] and products[1]
Mix [array.nested] after [[array]] to add to most recent array element
Cannot redefine static table as array or vice versa

Inline Tables

point = { x = 1, y = 2 } for compact single-line tables
Inline tables cannot span lines (until TOML 1.1)
Cannot add keys to inline table after definition—immutable once closed
Nested inline tables allowed but reduce readability

Types

Integers: decimal, hex 0xDEAD, octal 0o755, binary 0b1010
Underscores for readability: 1_000_000 is valid
Floats: 3.14, 5e-10, inf, nan (case-sensitive)
Booleans: true/false only—lowercase, no yes/no/on/off

Dates & Times

RFC 3339 format: 2024-01-15T14:30:00Z or with offset +05:30
Local datetime: 2024-01-15T14:30:00 (no timezone)
Local date: 2024-01-15; Local time: 14:30:00
Milliseconds supported: 14:30:00.123

Common Pitfalls

No null type—omit key entirely for optional values
Arrays must be homogeneous (TOML 1.0)—TOML 1.1 allows mixed types
Trailing commas not allowed in arrays or inline tables
Comment # only outside strings—no inline comment after value on same line works, but avoid ambiguity

---name: tomldescription: Write valid TOML configuration files with correct types and structure.--- ## Strings - Basic strings `"..."` support escapes: `\n`, `\t`, `\\`, `\"` - Literal strings `'...'` are raw—no escape sequences, backslash is literal - Multiline basic `"""..."""` allows newlines; leading newline after `"""` is trimmed - Multiline literal `'''...'''` for raw blocks; no escape processing ## Keys - Bare keys: alphanumeric, dash, underscore only—`key-name_1` valid - Quoted keys for special chars: `"key with spaces"` or `'key.with.dots'` - Dotted keys `a.b.c = 1` equivalent to nested tables—defines `[a.b]` implicitly - Keys are case-sensitive—`Key` and `key` are different ## Tables - `[table]` defines table; all following key-values belong to it until next header - `[a.b.c]` creates nested structure—parent tables created implicitly - Dotted keys under `[table]` extend it: `[fruit]` then `apple.color = "red"` works - Defining table after dotted key created it is error—order matters ## Arrays of Tables - `[[array]]` appends new table to array each time it appears - `[[products]]` twice creates `products[0]` and `products[1]` - Mix `[array.nested]` after `[[array]]` to add to most recent array element - Cannot redefine static table as array or vice versa ## Inline Tables - `point = { x = 1, y = 2 }` for compact single-line tables - Inline tables cannot span lines (until TOML 1.1) - Cannot add keys to inline table after definition—immutable once closed - Nested inline tables allowed but reduce readability ## Types - Integers: decimal, hex `0xDEAD`, octal `0o755`, binary `0b1010` - Underscores for readability: `1_000_000` is valid - Floats: `3.14`, `5e-10`, `inf`, `nan` (case-sensitive) - Booleans: `true`/`false` only—lowercase, no yes/no/on/off ## Dates & Times - RFC 3339 format: `2024-01-15T14:30:00Z` or with offset `+05:30` - Local datetime: `2024-01-15T14:30:00` (no timezone) - Local date: `2024-01-15`; Local time: `14:30:00` - Milliseconds supported: `14:30:00.123` ## Common Pitfalls - No null type—omit key entirely for optional values - Arrays must be homogeneous (TOML 1.0)—TOML 1.1 allows mixed types - Trailing commas not allowed in arrays or inline tables - Comment `#` only outside strings—no inline comment after value on same line works, but avoid ambiguity

Frequently asked questions