Agent skill

Writing Hashql Jexpr

HashQL J-Expr syntax for writing queries. An agent skill from hashintel/hash.

AGPL-3.0Auto-check passedDevelopment

Install Writing Hashql Jexpr

skills CLI

$ npx skills add hashintel/hash --skill writing-hashql-jexpr -a claude-code

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

GitHub CLI

$ gh skill install hashintel/hash writing-hashql-jexpr --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/hashintel/hash.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .claude/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .claude/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr

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 hashintel/hash --skill writing-hashql-jexpr -a codex

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

GitHub CLI

$ gh skill install hashintel/hash writing-hashql-jexpr --agent codex

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

Manual copy

$ git clone --depth 1 https://github.com/hashintel/hash.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .agents/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .agents/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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 hashintel/hash --skill writing-hashql-jexpr -a cursor

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

GitHub CLI

$ gh skill install hashintel/hash writing-hashql-jexpr --agent cursor

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

Manual copy

$ git clone --depth 1 https://github.com/hashintel/hash.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .cursor/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .cursor/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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/hashintel/hash.git --path .agents/skills/writing-hashql-jexpr

--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 hashintel/hash --skill writing-hashql-jexpr -a gemini-cli

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

GitHub CLI

$ gh skill install hashintel/hash writing-hashql-jexpr --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/hashintel/hash.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .gemini/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .gemini/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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 hashintel/hash writing-hashql-jexpr

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 hashintel/hash --skill writing-hashql-jexpr -a github-copilot

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

Manual copy

$ git clone --depth 1 https://github.com/hashintel/hash.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .github/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .github/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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 hashintel/hash --skill writing-hashql-jexpr -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 hashintel/hash writing-hashql-jexpr --agent opencode

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

Manual copy

$ git clone --depth 1 https://github.com/hashintel/hash.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/writing-hashql-jexpr .opencode/skills/writing-hashql-jexpr && 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 "writing-hashql-jexpr" agent skill from https://github.com/hashintel/hash/tree/main/.agents/skills/writing-hashql-jexpr into .opencode/skills/writing-hashql-jexpr/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "writing-hashql-jexpr", 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: writing-hashql-jexpr
GitHub stars: 1.7k
Token cost: ~1.2k tokens
SKILL.md length: 229 words
Files: 5 (incl. references)
Skills in repo: 17
Repo updated: Oct 7, 2026
First seen: Oct 7, 2026
Licence: AGPL-3.0

At a glance

HashQL J-Expr syntax for writing queries. An agent skill from hashintel/hash.

Writing J-Expr code
SKILL.md covers Expression Types, Paths (Strings), Function Calls (Arrays) and Data Constructors (Objects…, plus 5 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
Using literal/struct/list constructs

What it does

Writing Hashql Jexpr is an agent skill from hashintel/hash. HashQL J-Expr syntax for writing queries. Use when writing J-Expr code, using literal/struct/list constructs, understanding function call syntax, or working with HashQL query files (.jsonc).

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 5 other files, including reference files (for example `references/data-constructors.md`, `references/special-forms.md` and `references/syntax-reference.md`).

It sits in Development. The repository describes itself as: 🚀 The open-source, multi-tenant platform for self-building knowledge graphs and simulation. The licence is AGPL-3.0.

When your agent uses it

Writing J-Expr code
Using literal/struct/list constructs
Understanding function call syntax
Working with HashQL query files (.jsonc)

Example prompts

“/writing-hashql-jexpr”

What it can do on your machine

Read from SKILL.md and the folder at commit e189ab2. 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
No scripts in the folder and no shell commands in SKILL.md (its code samples are jsonc).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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

Writing Hashql Jexpr loads about 1.2k tokens when it runs, and up to ~8.3k if it reads all its reference files. Until then it costs about 54 tokens; SKILL.md has 229 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~54
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~8.3k

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 hashintel/hash at commit e189ab2, republished under its AGPL-3.0 licence (© hashintel). 229 words, ~1,221 tokens.

Download SKILL.mdSave it as .claude/skills/writing-hashql-jexpr/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.

name: writing-hashql-jexpr
description: HashQL J-Expr syntax for writing queries. Use when writing J-Expr code, using #literal/#struct/#list constructs, understanding function call syntax, or working with HashQL query files (.jsonc).
license: AGPL-3.0

Writing HashQL J-Expr

J-Expr is a JSON-based expression syntax for HashQL. It represents typed expressions using JSON primitives.

Expression Types

J-Expr has three expression types:

JSON Type	J-Expr Meaning
String	Path/identifier/symbol
Array	Function call
Object	Data constructor (with `#` keys)

Paths (Strings)

Strings are parsed as paths or identifiers:

jsonc

"x"                           // Simple variable
"vertex.id.entity_id"         // Dotted path access
"::core::types::String"       // Namespaced/rooted path
"::graph::head::entities"     // Graph function path

Function Calls (Arrays)

Arrays represent function calls: [function, arg1, arg2, ...]

jsonc

// Basic function call
["add", {"#literal": 1}, {"#literal": 2}]

// Namespaced function
["::graph::head::entities", ["::graph::tmp::decision_time_now"]]

// Labeled argument with :prefix in object
["greet", {":name": {"#literal": "Alice"}}]

// Shorthand labeled argument (string with :prefix)
["func", ":name"]

Data Constructors (Objects with # Keys)

Objects with special # keys construct data:

Key	Purpose	Example
`#literal`	Primitive values	`{"#literal": 42}`
`#struct`	Named fields	`{"#struct": {"x": ...}}`
`#list`	Variable-size ordered	`{"#list": [...]}`
`#tuple`	Fixed-size ordered	`{"#tuple": [...]}`
`#dict`	Key-value map	`{"#dict": {"k": ...}}`
`#type`	Type annotation	Used with other keys

Literals

jsonc

{"#literal": 42}
{"#literal": "hello"}
{"#literal": true}
{"#literal": null}
{"#literal": 3.14, "#type": "Float"}

Struct

jsonc

{"#struct": {"name": {"#literal": "Alice"}, "age": {"#literal": 30}}}
{"#struct": {"x": {"#literal": 1}}, "#type": "Point"}

List and Tuple

jsonc

{"#list": [{"#literal": 1}, {"#literal": 2}]}
{"#tuple": [{"#literal": 1}, {"#literal": "text"}]}

Dict

jsonc

{ "#dict": { "key": { "#literal": "value" } } }

Common Patterns

Let Binding

jsonc

["let", "varName", { "#literal": 10 }, ["add", "varName", { "#literal": 5 }]]

Function Definition

jsonc

["fn", {"#tuple": []}, {"#struct": {"vertex": "_"}}, "_", body_expr]

Conditionals

jsonc

["if", condition_expr, then_expr, else_expr]

Comparison

jsonc

["==", "left", "right"]
[">", {"#literal": 5}, {"#literal": 3}]

Do

Use #literal for all primitive values (numbers, strings, booleans, null)
Use :: prefix for namespaced paths
Use : prefix for labeled arguments
Combine #type with other constructors for type annotations

Don't

Don't use bare JSON numbers/booleans - wrap in {"#literal": ...}
Don't confuse #list (variable-size) with #tuple (fixed-size)
Don't use # prefix for labeled arguments (use :)
Don't nest # keys incorrectly - each object should have one primary # key

Examples

Entity query:

jsonc

["::graph::head::entities", ["::graph::tmp::decision_time_now"]]

Filtering with comparison:

jsonc

[
  "filter",
  "entities",
  [
    "fn",
    { "#tuple": [] },
    { "#struct": { "entity": "_" } },
    "_",
    ["==", "entity.draft_id", { "#literal": null }],
  ],
]

Struct with type:

jsonc

{ "#struct": { "value": { "#literal": 100 } }, "#type": "Amount" }

References

Syntax Reference - Paths, function calls, operators
Special Forms - Language constructs (if, let, fn, type, use, etc.)
Data Constructors - Typed data (#literal, #struct, #tuple, #list, #dict, #type)
Type DSL - Embedded type annotation syntax
Parser: libs/@local/hashql/syntax-jexpr/src/parser/
Object forms: libs/@local/hashql/syntax-jexpr/src/parser/object/
Type DSL: libs/@local/hashql/syntax-jexpr/src/parser/string/type.rs

Files

SKILL.md and 4 other files (references) in .agents/skills/writing-hashql-jexpr of hashintel/hash.

SKILL.md
references/data-constructors.md
references/special-forms.md
references/syntax-reference.md
references/type-dsl.md

Open the folder on GitHubat commit e189ab2

Compare with similar skills

Writing Hashql Jexpr 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.

Writing Hashql Jexpr compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Writing Hashql Jexpr this skillhashintel/hash	1.7k	—	~1.2k	Automated safety check: Pass	AGPL-3.0	today
Finishing a Development Branchobra/superpowers	296k	5 repos	~1.9k	Automated safety check: Pass	MIT	today
Typescript Advanced Typesrolling-scopes/rsschool-app	10k	24 repos	~4.2k	Automated safety check: Pass	MPL-2.0	3 days ago
PR Babysitteropeninterpreter/openinterpreter	69k	3 repos	~4.2k	Automated safety check: Pass	Apache-2.0	today
Code Review ChecklistshareAI-lab/learn-claude-code	78k	5 repos	~1.1k	Automated safety check: Pass	MIT	9 days ago
Greplooponyx-dot-app/onyx	32k	4 repos	~3.3k	Automated safety check: Pass	MIT	today

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Questions about Writing Hashql Jexpr

What does Writing Hashql Jexpr do?

HashQL J-Expr syntax for writing queries. An agent skill from hashintel/hash. Writing Hashql Jexpr is an agent skill from hashintel/hash. HashQL J-Expr syntax for writing queries.

When should I use Writing Hashql Jexpr?

Writing Hashql Jexpr fits situations like: writing J-Expr code; using literal/struct/list constructs; understanding function call syntax; working with HashQL query files (.jsonc).

How do I install Writing Hashql Jexpr in Claude Code?

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

How do I install Writing Hashql Jexpr in Codex?

Run `npx skills add hashintel/hash --skill writing-hashql-jexpr -a codex`. Or copy the skill folder (.agents/skills/writing-hashql-jexpr in hashintel/hash) into .agents/skills/writing-hashql-jexpr in your project. Codex loads it when a task matches its description.

Can I use Writing Hashql Jexpr 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 hashintel/hash --skill writing-hashql-jexpr -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/writing-hashql-jexpr, .gemini/skills/writing-hashql-jexpr, .github/skills/writing-hashql-jexpr and .opencode/skills/writing-hashql-jexpr in your project.

What does Writing Hashql Jexpr need to run?

SKILL.md names no scripts, command-line tools or credentials: Writing Hashql Jexpr is instructions for the agent only.

Does Writing Hashql Jexpr access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Writing Hashql Jexpr 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 Writing Hashql Jexpr use?

Writing Hashql Jexpr is published under the AGPL-3.0 licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Writing Hashql Jexpr use?

About 1.2k tokens (SKILL.md is roughly 4.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 7.1k tokens, read only when the agent opens those files.

What are the alternatives to Writing Hashql Jexpr?

Skills that share tags, products or a category with Writing Hashql Jexpr: Finishing a Development Branch (obra/superpowers, 296k stars), Typescript Advanced Types (rolling-scopes/rsschool-app, 10k stars), PR Babysitter (openinterpreter/openinterpreter, 69k stars) and Code Review Checklist (shareAI-lab/learn-claude-code, 78k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Writing Hashql Jexpr?

hashintel (a GitHub organization) maintains it in hashintel/hash, which has 1,668 GitHub stars. The repository holds 17 skills in this directory. The repository was last updated on October 7, 2026.

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

Install Writing Hashql Jexpr

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Writing HashQL J-Expr

Expression Types

Paths (Strings)

Function Calls (Arrays)

Data Constructors (Objects with # Keys)

Literals

Struct

List and Tuple

Dict

Common Patterns

Let Binding

Function Definition

Conditionals

Comparison

Do

Don't

Examples

References

Files

Compare with similar skills

Similar skills

More from hashintel/hash

Related

Questions about Writing Hashql Jexpr