OpenScript studies and strategies

Write a .oscript file and install it into strategies/openscript/, where it becomes a study or a strategy a trader can open in the editor, backtest on /trading, and deploy on an instrument.

Which path is this. Three unrelated things in this repository are called indicators, and they share nothing but the word:

• OpenScript (this skill) is a language, compiled to a program. Files are .oscript, and they can both draw and place orders.
• chart-indicator is a plain JavaScript descriptor on openalgo-charts, drawing only, loaded by the browser at runtime.
• openalgo.ta is a Python library used from the Python strategy host, scanners and backtests.

If the request names a .oscript file, the OpenScript editor, or a strategy to deploy on /trading, it is this one. If it is "add an indicator to my chart" with no more said, it is probably chart-indicator.

The one rule

Never write into strategies/openscript/ by hand. That folder holds two files per script, <name>.oscript and <name>.oscript.program.json, and the runner reads only the program. It never opens the source.

That makes two silent failures possible, and both matter more than a compile error:

• A source with no program is a strategy that cannot run. It saves, it opens in the editor, it appears in the list, and starting it is refused a minute later in a log nobody is reading.
• A program built from different text is worse. A run executes one script while a trader reads another.

So the two files are written together, from one compile, or neither is:

# 1. draft to a scratch file (never the openscript folder)
#    e.g. <scratchpad>/my_strategy.oscript

# 2. compile it the way the browser will
node .claude/skills/openscript/validate.mjs <scratch>/my_strategy.oscript

# 3. only on PASSED, install both files
node .claude/skills/openscript/validate.mjs <scratch>/my_strategy.oscript --install

#    with a different installed name:
node .claude/skills/openscript/validate.mjs <scratch>/draft.oscript --install --as mean-reversion.oscript

--install writes both files only when there are zero errors, and exits 1 otherwise. Before writing either, it checks that the hash the compiled program records matches the source it is about to write beside it, which is the same check the platform's own save route makes. A mismatched pair is refused and nothing is written, so the failure cannot be half-applied.

What a pass means

The compiler accepted the text: the names resolve, the types agree, the calls exist, the limits hold. Nothing here runs a single bar. It does not mean the strategy is any good, that its numbers are right, or that it will make money.

Some refusals wait for a bar, and a pass rules out none of them: a cell written outside its grid is OS4008 on the bar that writes it. OS6025, a bar handed over with no time, is the platform's data and not the script: report the instrument and timeframe rather than changing the script.

reference/strategies.md ends with the four steps between a compile and money, and they are not optional.

Read these before writing

Look a name up rather than recalling it. 350 names is more than anyone holds, and the dangerous failure is not reaching for a name that does not exist: it is reaching for a neighbour that computes something else, which compiles and reports a different strategy than the one that was meant.

Porting from another chart language

The installed compiler carries an importer for the widely used chart language whose scripts open with //@version=5 or //@version=6. Each statement comes across with its original meaning, or with a warning stating the difference, or as a comment with an error, all in the range OS9001 to OS9012, and what it hands back has been compiled. Save the original as <scratch>/original.txt, then from the repository root (the file is an argument, not standard input):

node --input-type=module -e "import { importScript } from './frontend/node_modules/openalgo-script/dist/core/index.js'; import { readFileSync } from 'node:fs'; const r = importScript(readFileSync(process.argv[1], 'utf8')); process.stdout.write(r.source); for (const f of r.findings) console.error(f.code, f.message)" <scratch>/original.txt > <scratch>/ported.oscript

The output is a draft, not a port. Read every finding: a warning marks a place where the numbers can differ from the original, and a line kept as a comment is behaviour that did not come across. Then take it through validate.mjs like any other draft.

To port a JavaScript chart indicator (an openalgo-charts descriptor handed to registerIndicator, with calc(bars, settings)) into a study, read reference/porting-from-javascript.md first: there is no importer for that direction, and several chart helpers share a name with a built-in that computes something else.

Three things that cost the most time

Ninety five of the 350 names are planned and not implemented in this version. The library describes a name whether or not a version implements it, so a name resolving is not a promise that it compiles. Reaching for one is OS2020. They are marked in reference/library.md. order.qtyForRisk is the one most likely to be reached for by accident, because it reads exactly like the call you want; whole families are planned, including all of leg.* and all of book.*.

buy and sell move a position by an amount; they do not set it to a side. sell(qty = lots) while long one lot leaves the position flat, not short. Nothing refuses it. It is the first entry in reference/pitfalls.md and the reason examples/stop-and-reverse.oscript exists.

A value that is absent is not zero. Every stateful call has a warmup, and arithmetic on an absent value is absent rather than zero, which is what keeps a signal from firing before its average exists. A script that substitutes a number during warmup, with orElse or otherwise, is quietly wrong for its first stretch of bars and looks like it works.

Keeping the skill honest

The generator and two checks, all three of which the CI job runs:

node .claude/skills/openscript/generate-reference.mjs   # rewrites reference/library.md
node .claude/skills/openscript/coverage.mjs             # must print COVERAGE COMPLETE
node .claude/skills/openscript/check-pitfalls.mjs       # must print PITFALLS VERIFIED

coverage.mjs holds the reference to the compiler in both directions (a name the compiler has and the page lacks fails, and so does a name the page teaches that the compiler does not have), checks that every planned name is marked, and checks that each shape an author asks for is demonstrated in an example that compiles, with the kind read from the compiled program rather than from the text.

check-pitfalls.mjs compiles both halves of every entry in reference/pitfalls.md: the wrong spelling must still produce the code named, and the fix offered must still come out clean. It also checks that the page and the script name the same set of codes, so neither can drift alone. Two claims on the first draft of that page were wrong, and this is what found them.

This skill describes openalgo-script 0.8.1, the compiler /trading pins, with the server engine openscript at the same version. OpenScript 0.9.0, with fixes to the backtest engine, is coming; when the pin moves to it, read its changelog for anything a backtest now reports differently and say so here.

Bumping openalgo-script means updating this skill in the same change, the way a chart bump does. Run the generator, run both checks, then update the prose by hand: the generator owns the name table and nothing generates the teaching.