Diagrams
Draw diagram
Check, describe, and draw a diagram.
POST
/v1/diagrams/drawTL;DR
| Question | Answer |
|---|---|
| What does it do? | Check, describe, and draw a diagram. |
| Which tool does the same? | draw_diagram |
| What does it take? | A JSON body of type DrawDiagramInput. |
| What does it return? | Status 200 with a body of type DrawDiagramResponse. |
| What can go wrong? | 400 the body failed schema validation; 401 the api key is missing or not valid; 403 the account is on the free plan, which does not include the rest drawing and checking routes (plan.rest_not_included); 413 the body is larger than the size cap; 429 too many requests. Every failure uses the one error envelope. |
What it does
Validates the source and, when it is valid, also returns the quality warnings, a plain-text outline, the natural size, and the SVG for the light theme, the dark theme, or both. Source with errors is a normal 200 result with valid false, every error with its line, column, and hint, and nothing drawn, so a caller fixes the source and calls again. Prefer this route over calling the validate, outline, and render routes separately: it does the work of all three in one request. Use the single routes only when one fine-grained step is all you need.
Request body
The body has the type DrawDiagramInput.
| Field | Type | Required | Description |
|---|---|---|---|
source | string | yes | Diagram source. The first line is the header: flow "Title", sequence "Title", schema "Title", git "Title", gantt "Title", class "Title", state "Title", timeline "Title", journey "Title", mindmap "Title", treemap "Title", pie "Title", quadrant "Title", layers "Title", c4 "Title", matrix "Title", sankey "Title", xychart "Title", tree "Title", or swimlane "Title". at least 1 character; at most 50000 characters. |
themes | "light" | "dark" | "both" | no | light, dark, or both (the default): the light picture and the dark one a dark page needs. default "both". |
detail | "summary" | "full" | no | summary (the default), or full: the whole outline, and the source embedded in each SVG. default "summary". |
svg | "auto" | "always" | "never" | no | auto (the default) returns the SVGs, but over MCP leaves them out when the answer would be too big for a client (picturesOmitted). always returns them at any size. never draws nothing, which is cheaper. The HTTP API treats auto as always. default "auto". |
embedSource | boolean | no | Write the source into each SVG so read_diagram can give it back. Set it when you save the SVG in a repository or publish it to edit later; anyone with the file or link can then read the source. default false. |
settings | object | no | The repo's plotwork.config.json, if any. Schema: https://docs.plotwork.dev/schemas/plotwork.config.json (opens in a new tab). |
Responses
| Status | Meaning | Body |
|---|---|---|
| 200 | The check, and when valid the outline and pictures. | DrawDiagramResponse |
| 400 | The body failed schema validation. | ErrorResponse |
| 401 | The API key is missing or not valid. | ErrorResponse |
| 403 | The account is on the Free plan, which does not include the REST drawing and checking routes (plan.rest_not_included). | ErrorResponse |
| 413 | The body is larger than the size cap. | ErrorResponse |
| 429 | Too many requests. | ErrorResponse |
Response body
A 200 answer has the type DrawDiagramResponse.
| Field | Type | Required | Description |
|---|---|---|---|
valid | boolean | yes | True when the source has no errors. When false, nothing was drawn: fix the errors and call again. |
kind | string | null | yes | The diagram kind, or null when the header could not be read. |
errors | Diagnostic[] | yes | Every error found in one pass, each with line, column, and a hint. Empty when valid. |
errors[].code | "E100" | "E101" | "E110" | "E111" | "E120" | "E121" | "E122" | "E123" | "E124" | "E125" | "E130" | "E131" | "E132" | "E133" | "E134" | "E135" | "E136" | "E137" | "E138" | "E139" | "E140" | "W200" | "W201" | "W202" | "W203" | "W204" | "W205" | "W206" | "W207" | "W500" | "M100" | "M101" | "M102" | "M103" | "M104" | "M110" | "M200" | "M201" | "M202" | "M203" | "M204" | "M205" | "M206" | "M207" | "M208" | "M209" | "M210" | "M211" | "M212" | "M213" | "M214" | "M215" | "M216" | "M217" | "M218" | "E300" | "E301" | "E302" | "E303" | "E304" | "W300" | "W301" | "W302" | "W303" | "M120" | "M220" | "M221" | "M222" | "E340" | "E341" | "E342" | "E343" | "E344" | "E345" | "W320" | "W321" | "W322" | "W323" | "M240" | "M241" | "M242" | "E360" | "E361" | "E362" | "E363" | "E364" | "E365" | "E366" | "E367" | "W330" | "W331" | "W332" | "W333" | "W334" | "M250" | "M251" | "E400" | "E401" | "E402" | "E403" | "W350" | "W351" | "W352" | "W353" | "M270" | "M271" | "E420" | "E421" | "E422" | "E423" | "E424" | "W360" | "W361" | "W362" | "W363" | "W364" | "M180" | "M280" | "M281" | "M282" | "E320" | "E321" | "E322" | "E323" | "E324" | "E325" | "E326" | "E327" | "E328" | "E329" | "E330" | "W310" | "W311" | "W312" | "W313" | "W314" | "M130" | "M131" | "M132" | "M230" | "M231" | "M232" | "M233" | "M234" | "M235" | "M236" | "M237" | "M238" | "E380" | "E381" | "E382" | "E383" | "W340" | "W341" | "W342" | "W343" | "M260" | "I100" | "I101" | "I102" | "I103" | "I104" | "I105" | "I200" | "I201" | "I202" | "I203" | "I204" | "I206" | "R100" | "R101" | "R200" | "R201" | "R202" | "R203" | "R204" | "R205" | "R206" | "R207" | "S100" | "S200" | "S101" | "S102" | "S103" | "S104" | "S201" | "S202" | "S203" | yes | Stable code to branch on; E-codes are errors, W-codes are warnings. |
errors[].severity | "error" | "warning" | yes | Errors stop rendering; warnings never do. |
errors[].message | string | yes | What is wrong, in one sentence. |
errors[].line | integer | yes | 1-based line in the submitted source. minimum 1. |
errors[].column | integer | yes | 1-based column in that line. minimum 1. |
errors[].length | integer | yes | Number of characters the problem covers. minimum 1. |
errors[].hint | string | null | yes | A concrete suggestion for fixing it, or null. |
warnings | Diagnostic[] | yes | Quality warnings for a valid diagram: too dense, too wide, text cut, unconnected nodes, and suggestions for an icon or a group type. Empty when invalid. |
warnings[].code | "E100" | "E101" | "E110" | "E111" | "E120" | "E121" | "E122" | "E123" | "E124" | "E125" | "E130" | "E131" | "E132" | "E133" | "E134" | "E135" | "E136" | "E137" | "E138" | "E139" | "E140" | "W200" | "W201" | "W202" | "W203" | "W204" | "W205" | "W206" | "W207" | "W500" | "M100" | "M101" | "M102" | "M103" | "M104" | "M110" | "M200" | "M201" | "M202" | "M203" | "M204" | "M205" | "M206" | "M207" | "M208" | "M209" | "M210" | "M211" | "M212" | "M213" | "M214" | "M215" | "M216" | "M217" | "M218" | "E300" | "E301" | "E302" | "E303" | "E304" | "W300" | "W301" | "W302" | "W303" | "M120" | "M220" | "M221" | "M222" | "E340" | "E341" | "E342" | "E343" | "E344" | "E345" | "W320" | "W321" | "W322" | "W323" | "M240" | "M241" | "M242" | "E360" | "E361" | "E362" | "E363" | "E364" | "E365" | "E366" | "E367" | "W330" | "W331" | "W332" | "W333" | "W334" | "M250" | "M251" | "E400" | "E401" | "E402" | "E403" | "W350" | "W351" | "W352" | "W353" | "M270" | "M271" | "E420" | "E421" | "E422" | "E423" | "E424" | "W360" | "W361" | "W362" | "W363" | "W364" | "M180" | "M280" | "M281" | "M282" | "E320" | "E321" | "E322" | "E323" | "E324" | "E325" | "E326" | "E327" | "E328" | "E329" | "E330" | "W310" | "W311" | "W312" | "W313" | "W314" | "M130" | "M131" | "M132" | "M230" | "M231" | "M232" | "M233" | "M234" | "M235" | "M236" | "M237" | "M238" | "E380" | "E381" | "E382" | "E383" | "W340" | "W341" | "W342" | "W343" | "M260" | "I100" | "I101" | "I102" | "I103" | "I104" | "I105" | "I200" | "I201" | "I202" | "I203" | "I204" | "I206" | "R100" | "R101" | "R200" | "R201" | "R202" | "R203" | "R204" | "R205" | "R206" | "R207" | "S100" | "S200" | "S101" | "S102" | "S103" | "S104" | "S201" | "S202" | "S203" | yes | Stable code to branch on; E-codes are errors, W-codes are warnings. |
warnings[].severity | "error" | "warning" | yes | Errors stop rendering; warnings never do. |
warnings[].message | string | yes | What is wrong, in one sentence. |
warnings[].line | integer | yes | 1-based line in the submitted source. minimum 1. |
warnings[].column | integer | yes | 1-based column in that line. minimum 1. |
warnings[].length | integer | yes | Number of characters the problem covers. minimum 1. |
warnings[].hint | string | null | yes | A concrete suggestion for fixing it, or null. |
summary | string | null | yes | One-line description of the diagram, usable as alt text; null when invalid. |
outline | string[] | yes | The diagram as plain text in reading order, to check it says what you meant; empty when invalid. |
outlineTruncated | boolean | yes | True when the summary level cut the outline short. Call again with detail "full" to read all of it. |
size | object | null | yes | Natural size of the laid-out diagram; null when invalid. |
size.width | integer | yes | Width in px. minimum 1. |
size.height | integer | yes | Height in px. minimum 1. |
quality | object | no | How clean the picture looks (score, grade, measures) and up to three changes that would help; read it instead of looking. Absent when invalid. |
quality.score | integer | yes | 0 to 100; 100 is a picture with nothing to fix. The same diagram always gets the same score. minimum 0; maximum 100. |
quality.grade | "clean" | "fair" | "cluttered" | yes | clean is 85 or more, fair 60 or more, cluttered below. |
quality.measures | object | yes | What the score is made from: crossings, lineOverBox, labelOverlaps, smallestTextPx (in an 880px column), aspectRatio, emptySpace (0 to 1), longestLine (px), detour (1 is straight), the counts of boxes, lines, labels, series, and slices, and any measure the kind adds. |
quality.hints | string[] | yes | Up to three changes, the one worth most first, each naming the statement or option to edit. |
quality.line | string | yes | The grade, the score, and the first hint in one line. |
notices | Note[] | no | Information notes, such as an icon alias drawn as the real icon; absent when there is none. |
notices[].code | string | yes | A stable code, such as I122 for an icon alias. |
notices[].severity | "info" | yes | A note never stops a drawing and is not a warning. |
notices[].message | string | yes | |
notices[].line | integer | yes | minimum 1. |
notices[].column | integer | yes | minimum 1. |
notices[].length | integer | yes | minimum 1. |
notices[].hint | string | null | yes | The text to write instead. |
renders | object[] | yes | One picture per requested color scheme, light first; empty when invalid, when svg is never, and when every picture was left out (see picturesOmitted). |
renders[].theme | "light" | "dark" | yes | The color scheme this picture is drawn in. |
renders[].svg | string | yes | Self-contained SVG markup with an accessible title and description. |
renders[].size | Size | yes | Natural size of a rendered diagram in px. |
renders[].size.width | integer | yes | Width in px. minimum 1. |
renders[].size.height | integer | yes | Height in px. minimum 1. |
picturesOmitted | object | no | Present only when pictures were left out because the answer would have been too big for an AI client to read in one piece. |
picturesOmitted.themes | ("light" | "dark")[] | yes | The color schemes whose pictures were left out. |
picturesOmitted.characters | integer | yes | How many characters the pictures left out came to. |
picturesOmitted.limit | integer | yes | The most characters one answer may hold before the pictures are left out. |
picturesOmitted.why | string | yes | Why they were left out, and what to do. |
viewUrl | string | no | A link that shows a valid diagram in a browser; give it to the person who wants to look. The source is in the part after #, never sent to a server, but anyone with the link can read it. Absent when too long; next says so. |
pngUrl | string | no | The viewUrl with &download=png: opening it in a browser saves the diagram as a PNG for Slack, email, or a wiki. The PNG is drawn in the person's browser, not on a server, so it is a link to open, not an image address to embed. Absent when too long. |
svgUrl | string | no | The viewUrl with &download=svg: a person opens it to download the SVG. Not a file address for curl; use saveCommand. Absent when too long. |
saveCommand | string | no | Run in a shell to save the SVG into the repository: the CLI decodes the link locally, fetches nothing, and embeds the source. Set --out to the path; add --theme dark for dark. Absent when too long. |
next | string | yes | The next step in one sentence. |
See also
| Doc | Why |
|---|---|
| API reference | Every endpoint, and the error envelope |
| Schemas | Every request and response type |
draw_diagram | The same operation as an MCP tool |
| Tool reference | The operations as callable tools |