Design Stair

Walk one stair flight through the fifteen dimensional items that stair codes regulate, and report which ones pass, which fail, and which could not be checked. The checklist is the same everywhere. The numbers are not, so the numbers come from you.

Workflow

Step 1. Establish the code

Ask, in one message:

1. Which code governs this project, and which edition? (for example IBC 2021, OBC 2024, NBC 2020, or your national code)
2. Is there a separate accessibility standard in play? (for example 2010 ADA, CSA B651, or an annex of the same code)
3. Is this stair on an accessible route? If no, the accessibility rows are dropped.
4. How will you supply the limits? Type them as we go, paste the clause text, or name a file I should read.

Record the answers verbatim. Every output row carries the code name and edition, so a table can be read a year later without guessing which cycle it came from.

Read the profile first, if there is one. If docs/jurisdiction.md exists, read it before asking anything else and say which of the checklist rows it already answers. Those are not asked again. A row it holds with not cited in the Clause column stays not cited in the output and is never promoted on the way through. Where the file is absent nothing changes: every limit is asked for exactly as below. jurisdiction-profile is the skill that writes and extends that file.

If the geometry is curved, spiral, winder, or alternating tread, stop here and say so.

Step 2. Collect the geometry

Ask for these. Treat anything unstated as missing, and never fill one in with a typical value.

• Clear width, and the occupant load the stair serves if width depends on it
• Headroom
• Riser height, giving max and min across the flight if they differ
• Tread depth, giving max and min if they differ
• Nosing projection, radius, and underside angle
• Landing depth
• Number of risers, or vertical rise between landings
• Handrail height above the nosing line
• Handrail clearance from the wall
• Handrail cross section: diameter if circular, perimeter and maximum dimension if not
• Handrail extension beyond the top riser, and beyond the bottom riser
• Handrails on both sides, yes or no
• Open risers, yes or no
• Slip resistance provided, yes or no, and whether the stair is exposed to wet conditions

Step 3. Collect the limits, one item at a time

For each row in the checklist below, ask for the limit and how it is cited. Accept any of three answers, and take nothing beyond them.

1. A typed limit. "Riser max 180 mm." Record it, and ask which clause it came from.
2. Pasted clause text. Read the value out of what was pasted and quote the sentence back so it can be checked.
3. A file to read. Read it, quote the sentence, and cite the file and line.

If none of the three arrives, mark the row unverified and move on. Do not offer a value, do not search for one, and do not treat a commonly known number as exempt from this.

When a limit arrives that docs/jurisdiction.md did not already hold, offer to write it there with its clause, so the next run does not ask for it again. Never write a row the user did not supply.

The checklist:

#	Item	Applies to
1	Clear width	all
2	Headroom	all
3	Riser height	all
4	Tread depth	all
5	Riser and tread uniformity tolerance	all
6	Nosing profile and projection	all
7	Landing depth	all
8	Vertical rise between landings	all
9	Handrail height	all
10	Handrail clearance from wall	all
11	Handrail cross section and graspability	all
12	Handrail extensions, top and bottom	all
13	Handrails required on both sides	all
14	Open risers permitted	accessible route
15	Slip resistance	wet conditions

Rows 14 and 15 drop out when they do not apply. Rows 1 through 13 always appear, even if every one of them ends up unverified, because an empty row is the useful part of the output.

Step 4. Compare and report

One table, in the chat:

Item	Limit	Cited as	Actual	Status

• Limit: what was supplied, in the units it was supplied in. Do not convert.
• Cited as: code, edition, and clause, or the file and line, or not cited if a bare number was given.
• Actual: the dimension provided.
• Status: pass, fail, unverified (no limit supplied), missing (no dimension supplied), or n/a.

Then a four line summary: how many passed, how many failed, how many are unverified, and what to supply to close the unverified rows.

End with the sentence that makes the table safe to hand to someone else:

Limits in this table came from you, not from me. I compared numbers and did not supply any. Unverified rows were not checked at all.

Step 5. Save, if asked

Ask whether to write the table to a file, and where. Write it directly. There is no template and no script.

Rules

• Never supply a code value. Not from memory, not from a search, not from a figure that appears in this file. There are none in this file.
• Never convert units. If a limit arrives in millimetres and a dimension in inches, say so and ask which to use. A silent conversion is a wrong number with the rounding hidden.
• A row is only checked if it has both a limit and a dimension. Anything else is unverified or missing, and both are counted in the summary.
• Every limit carries its citation through to the output, or is marked not cited so the reader knows.
• Stop the run for curved, spiral, winder, and alternating tread geometry rather than checking the rows that happen to fit.

Anti-patterns

• Filling a limit from recall because it is well known. Well known values are exactly the ones that get carried across an edition change without anyone noticing.
• Searching the web for a clause and quoting it as the limit. Search is reliable for finding which code governs and unreliable for quoting it correctly, and a quote that is 95% right reads identically to one that is right.
• Reporting only the rows that could be checked. The unverified rows are what tell the reader how much of the stair was actually looked at.
• Converting inches to millimetres, or rounding a supplied limit to a neater number.
• Bundling a table of values into this skill later. It has none on purpose, and a bundled table goes stale silently while continuing to look authoritative.
• Continuing past Step 1 without an edition. A clause number without an edition is not a citation.

Resources

None. This skill is one file. Output is written directly at the path you name.