Feeling sure is not the same as being sure.

LLMs make things that look right. Forma hands back things that passed. In seconds, or with a plain no.

Starting with charts and figures · see what is live →

A line chart of monthly active users in 2025, months Jan to Dec in calendar order on x (not alphabetical), users in thousands on y: 12.4, 13.1, 14.8, 15.2, 16.9, 18.3, 17.6, 18.9, 21.2, 22.8, 24.1, 26.5. Title: Monthly active users, 2025.

Recorded from production · 2026-10-01 · each step is a real call you can make

01
Read the catalogue rather than guess a name. Free.
list_oracles {}
→ 3 oracles · chart, vector-graphics, coverage-policy
02
The chart is checked against its rules, and against what Chart.js can draw, before it answers.
ask_oracle · chart · chartjs · the intent above
→ valid · chart@6baf09f0 · 1 credit

{
  "type": "line",
  "data": {
    "labels": [
      "Jan",
      "Feb",
      "Mar",
      "Apr",
      "May",
      "Jun",
      "Jul",
      "Aug",
      "Sep",
      "Oct",
      "Nov",
      "Dec"
    ],
    "datasets": [
      {
        "type": "line",
        "fill": false,
        "pointRadius": 0,
        "data": [
          12.4,
          13.1,
          14.8,
          15.2,
          16.9,
          18.3,
          17.6,
          18.9,
          21.2,
          22.8,
          24.1,
          26.5
        ]
      }
    ]
  },
  "options": {
    "plugins": {
      "title": {
        "display": true,
        "text": "Monthly active users, 2025"
      },
      "legend": {
        "display": false
      }
    },
    "scales": {
      "x": {
        "type": "category",
        "title": {
          "display": true,
          "text": "date (month)"
        }
      },
      "y": {
        "type": "linear",
        "title": {
          "display": true,
          "text": "Users (thousands)"
        },
        "beginAtZero": true
      }
    }
  }
}

{
  "oracle": "chart",
  "format": "chartjs",
  "status": "valid",
  "credits": 1,
  "result": {
    "type": "line",
    "data": {
      "labels": [
        "Jan",
        "Feb",
        "Mar",
        "Apr",
        "May",
        "Jun",
        "Jul",
        "Aug",
        "Sep",
        "Oct",
        "Nov",
        "Dec"
      ],
      "datasets": [
        {
          "type": "line",
          "fill": false,
          "pointRadius": 0,
          "data": [
            12.4,
            13.1,
            14.8,
            15.2,
            16.9,
            18.3,
            17.6,
            18.9,
            21.2,
            22.8,
            24.1,
            26.5
          ]
        }
      ]
    },
    "options": {
      "plugins": {
        "title": {
          "display": true,
          "text": "Monthly active users, 2025"
        },
        "legend": {
          "display": false
        }
      },
      "scales": {
        "x": {
          "type": "category",
          "title": {
            "display": true,
            "text": "date (month)"
          }
        },
        "y": {
          "type": "linear",
          "title": {
            "display": true,
            "text": "Users (thousands)"
          },
          "beginAtZero": true
        }
      }
    }
  },
  "verified_by": "chart@6baf09f0",
  "figure": {
    "drawable": false,
    "reason": "no renderer can draw chartjs"
  }
}

Line chart of monthly active users through 2025, in thousands, rising from 12.4 in January to 26.5 in December

Drawn by Chart.js from the returned config. Chart.js is not drawn by Forma's servers: the answer is the config, and your page draws it. The numbers are the ones given in the prompt, January's 12.4 thousand to December's 26.5.

Line chart of API request latency over one day, two lines: p50 and p99, in ms, by hour 0 to 23. p50: 42,40,39,38,38,40,45,58,72,80,84,86,85,88,90,87,83,76,64,55,50,47,45,43. p99: 120,115,110,108,110,118,140,190,260,310,330,345,338,352,365,350,320,280,220,180,160,145,135,125. x axis: hour of day, y axis: latency (ms).

Recorded from production · 2026-09-30 · each step is a real call you can make

01
Read the catalogue rather than guess a name. Free.
list_oracles {}
→ 3 oracles · chart, vector-graphics, coverage-policy
02
The chart is checked against its rules, and against what Plotly can draw, before it answers.
ask_oracle · chart · plotly · the intent above
→ valid · chart@6baf09f0 · 1 credit

{
  "data": [
    {
      "type": "scatter",
      "mode": "lines",
      "x": [
        0,
        1,
        2,
        3,
        4,
        5,
        6,
        7,
        8,
        9,
        10,
        11,
        12,
        13,
        14,
        15,
        16,
        17,
        18,
        19,
        20,
        21,
        22,
        23
      ],
      "y": [
        42,
        40,
        39,
        38,
        38,
        40,
        45,
        58,
        72,
        80,
        84,
        86,
        85,
        88,
        90,
        87,
        83,
        76,
        64,
        55,
        50,
        47,
        45,
        43
      ],
      "name": "p50"
    },
    {
      "type": "scatter",
      "mode": "lines",
      "x": [
        0,
        1,
        2,
        3,
        4,
        5,
        6,
        7,
        8,
        9,
        10,
        11,
        12,
        13,
        14,
        15,
        16,
        17,
        18,
        19,
        20,
        21,
        22,
        23
      ],
      "y": [
        120,
        115,
        110,
        108,
        110,
        118,
        140,
        190,
        260,
        310,
        330,
        345,
        338,
        352,
        365,
        350,
        320,
        280,
        220,
        180,
        160,
        145,
        135,
        125
      ],
      "name": "p99"
    }
  ],
  "layout": {
    "title": {
      "text": "API Request Latency by Hour"
    },
    "xaxis": {
      "title": {
        "text": "Hour of day"
      },
      "type": "linear",
      "rangemode": "tozero"
    },
    "yaxis": {
      "title": {
        "text": "Latency (ms)"
      },
      "type": "linear",
      "rangemode": "tozero"
    },
    "legend": {
      "title": {
        "text": "percentile"
      }
    }
  }
}

{
  "oracle": "chart",
  "format": "plotly",
  "status": "valid",
  "credits": 1,
  "result": {
    "data": [
      {
        "type": "scatter",
        "mode": "lines",
        "x": [
          0,
          1,
          2,
          3,
          4,
          5,
          6,
          7,
          8,
          9,
          10,
          11,
          12,
          13,
          14,
          15,
          16,
          17,
          18,
          19,
          20,
          21,
          22,
          23
        ],
        "y": [
          42,
          40,
          39,
          38,
          38,
          40,
          45,
          58,
          72,
          80,
          84,
          86,
          85,
          88,
          90,
          87,
          83,
          76,
          64,
          55,
          50,
          47,
          45,
          43
        ],
        "name": "p50"
      },
      {
        "type": "scatter",
        "mode": "lines",
        "x": [
          0,
          1,
          2,
          3,
          4,
          5,
          6,
          7,
          8,
          9,
          10,
          11,
          12,
          13,
          14,
          15,
          16,
          17,
          18,
          19,
          20,
          21,
          22,
          23
        ],
        "y": [
          120,
          115,
          110,
          108,
          110,
          118,
          140,
          190,
          260,
          310,
          330,
          345,
          338,
          352,
          365,
          350,
          320,
          280,
          220,
          180,
          160,
          145,
          135,
          125
        ],
        "name": "p99"
      }
    ],
    "layout": {
      "title": {
        "text": "API Request Latency by Hour"
      },
      "xaxis": {
        "title": {
          "text": "Hour of day"
        },
        "type": "linear",
        "rangemode": "tozero"
      },
      "yaxis": {
        "title": {
          "text": "Latency (ms)"
        },
        "type": "linear",
        "rangemode": "tozero"
      },
      "legend": {
        "title": {
          "text": "percentile"
        }
      }
    }
  },
  "verified_by": "chart@6baf09f0",
  "figure": {
    "drawable": false,
    "reason": "no renderer can draw plotly"
  }
}

Line chart, API request latency by hour: p50 between 38 and 90 ms, p99 between 108 and 365 ms, both peaking in the early afternoon

Drawn by Plotly from the returned figure. Plotly is not drawn by Forma's servers: the answer is the figure, and your page draws it. The numbers are the ones given in the prompt; p99 peaks at 365 ms at hour 14.

A binary search tree built by inserting the keys 8, 3, 10, 1, 6, 14, 4, 7, 13 in that order. Draw each node as a circle labelled with its key, edges from parent to child, left children to the left and right children to the right.

Recorded from production · 2026-09-30 · each step is a real call you can make

01
Read the catalogue rather than guess a name. Free.
list_oracles {}
→ 3 oracles · chart, vector-graphics, coverage-policy
02
Where each key goes is worked out for you, and the figure is held to its rules before Forma answers.
ask_oracle · vector-graphics · the intent above
→ valid · vector-graphics@c738bf88 · 1 credit
03
The answer says it is drawable, so the agent shows it.
show_figure {"figure_token":"fig_<token>"}
→ drawn inline, source on a second tab

\begin{tikzpicture}[x=1pt,y=1pt]
  \path[use as bounding box] (0,0) rectangle (276,132.15);
  \draw[draw=black!45,line width=0.4pt] (138,114.02) -- (58.08,82.06);
  \draw[draw=black!45,line width=0.4pt] (138,114.02) -- (217.92,82.06);
  \draw[draw=black!45,line width=0.4pt] (58.08,82.06) -- (18.12,50.09);
  \draw[draw=black!45,line width=0.4pt] (58.08,82.06) -- (98.04,50.09);
  \draw[draw=black!45,line width=0.4pt] (98.04,50.09) -- (76.73,18.12);
  \draw[draw=black!45,line width=0.4pt] (98.04,50.09) -- (119.35,18.12);
  \draw[draw=black!45,line width=0.4pt] (217.92,82.06) -- (257.88,50.09);
  \draw[draw=black!45,line width=0.4pt] (257.88,50.09) -- (236.57,18.12);
  \filldraw[draw=black,line width=0.6pt,fill=white] (138,114.02) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (58.08,82.06) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (217.92,82.06) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (18.12,50.09) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (98.04,50.09) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (257.88,50.09) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (76.73,18.12) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (119.35,18.12) circle[radius=10.12pt];
  \filldraw[draw=black,line width=0.6pt,fill=white] (236.57,18.12) circle[radius=10.12pt];
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (138,114.02) {8};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (58.08,82.06) {3};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (217.92,82.06) {10};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (18.12,50.09) {1};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (98.04,50.09) {6};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (257.88,50.09) {14};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (76.73,18.12) {4};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (119.35,18.12) {7};
  \node[text=black,anchor=center,font=\fontsize{10pt}{12pt}\selectfont] at (236.57,18.12) {13};
\end{tikzpicture}

{
  "oracle": "vector-graphics",
  "format": "tikz",
  "status": "valid",
  "credits": 1,
  "result": "\\begin{tikzpicture}[x=1pt,y=1pt]\n  \\path[use as bounding box] (0,0) rectangle (276,132.15);\n  \\draw[draw=black!45,line width=0.4pt] (138,114.02) -- (58.08,82.06);\n  \\draw[draw=black!45,line width=0.4pt] (138,114.02) -- (217.92,82.06);\n  \\draw[draw=black!45,line width=0.4pt] (58.08,82.06) -- (18.12,50.09);\n  \\draw[draw=black!45,line width=0.4pt] (58.08,82.06) -- (98.04,50.09);\n  \\draw[draw=black!45,line width=0.4pt] (98.04,50.09) -- (76.73,18.12);\n  \\draw[draw=black!45,line width=0.4pt] (98.04,50.09) -- (119.35,18.12);\n  \\draw[draw=black!45,line width=0.4pt] (217.92,82.06) -- (257.88,50.09);\n  \\draw[draw=black!45,line width=0.4pt] (257.88,50.09) -- (236.57,18.12);\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (138,114.02) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (58.08,82.06) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (217.92,82.06) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (18.12,50.09) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (98.04,50.09) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (257.88,50.09) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (76.73,18.12) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (119.35,18.12) circle[radius=10.12pt];\n  \\filldraw[draw=black,line width=0.6pt,fill=white] (236.57,18.12) circle[radius=10.12pt];\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (138,114.02) {8};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (58.08,82.06) {3};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (217.92,82.06) {10};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (18.12,50.09) {1};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (98.04,50.09) {6};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (257.88,50.09) {14};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (76.73,18.12) {4};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (119.35,18.12) {7};\n  \\node[text=black,anchor=center,font=\\fontsize{10pt}{12pt}\\selectfont] at (236.57,18.12) {13};\n\\end{tikzpicture}\n",
  "verified_by": "vector-graphics@c738bf88",
  "figure": {
    "drawable": true,
    "target": "tikz",
    "token": "fig_<token>"
  }
}

Drawn by Forma's figure engine from the returned TikZ. You can check it in the source: read the nodes left to right by x and the keys come out sorted, 1 3 4 6 7 8 10 13 14, which is what makes it a search tree.

01 Why Forma

Ask for it. Get it back checked.

Models sound certain.

Ask a model for code, a configuration, a diagram or a report, and the answer comes back fluent and confident, whether it is right or not.

You feel like you can trust it. You know you can't.

So you check every answer by hand, or you ship it and hope nobody looks closely.

Forma gives you a reason to trust it.

Every answer that passes says which version of the rules it passed. If it cannot pass, you are told, plainly.

Fast

Most answers come back in about two seconds. In our tests, frontier models took twenty to thirty to answer the same requests, unchecked.

Learn more →

Checked, with a receipt

Every answer that passes carries the version of the rules it passed. If it cannot pass, you get a plain no and the reason, not something plausible and wrong.

Learn more →

Works where you work

MCP for Claude, ChatGPT, Cursor, VS Code, Windsurf and Codex; HTTP and CI for code, where invalid fails the build; the console for people.

Learn more →

A price you can predict

One credit per answer, a cent each, however long the request. No token meter.

Learn more →

02 Who it is for

Wherever model output has to be right.

Teams building agents

Give an agent tools whose answers are checked, so it can act on them without a person reading every one.

Products and pipelines

Put model output into a product or a build with a verdict a program can act on: valid, invalid or error.

Anyone who publishes it

Reports, papers, docs, slides. When your name is on it, “it looked right” is not enough.

Teams who answer for it

Keep the rules version with the output, and you can say later exactly which version it passed.

03 Live today

Starting with charts and figures.

The first two products: charts in Vega-Lite, Plotly, ECharts, Chart.js or gnuplot, and figures in TikZ, MetaPost or PiCTeX. Each answer below is real, shown with the request that produced it, and every number in each chart's data is in its request. The tag beside each answer, such as chart@6baf09f0, is the version of the rules it passed.

Line chart of monthly active users through 2025, in thousands — chart · chartjs
“A line chart of monthly active users in 2025, months Jan to Dec in calendar order on x (not alphabetical), users in thou…”
valid · `chart@6baf09f0`
For analysts →

Line chart, API request latency by hour: p50 and p99, both peaking in the early afternoon — chart · plotly
“Line chart of API request latency over one day, two lines: p50 and p99, in ms, by hour 0 to 23. p50: 42,40,39,38,38,40,4…”
valid · `chart@6baf09f0`
For developers →

Scatter plot of car weight against fuel economy, petrol and diesel — chart · plotly
“A scatter plot of car weight against fuel economy, two groups as separately coloured marker series with a legend. Petrol…”
valid · `chart@6baf09f0`
For students and scientists →

vector-graphics · tikz

“A binary search tree built by inserting the keys 8, 3, 10, 1, 6, 14, 4, 7, 13 in that order. Draw each node as a circle…”

valid · vector-graphics@c738bf88

For researchers →

A Merkle tree: Root = H(ABCD) over H(AB) and H(CD), over H(A) to H(D), over data blocks A to D — vector-graphics · tikz
“A Merkle tree over four data blocks. Leaves: H(A), H(B), H(C), H(D) as boxes. Their parents: H(AB) above H(A) and H(B),…”
valid · `vector-graphics@c738bf88`
For researchers →

vector-graphics · tikz

“Triangle ABC with the midpoints of each side, the three medians, and the centroid G where they meet; check that each med…”

valid · vector-graphics@c738bf88

For educators →

Forma Visuals

These are the first two. What should Forma check next? Tell us what your models write.

04 Limits

Read this before you rely on it.

What “valid” means: the check covers form, not intent. A valid chart of the wrong column is still valid. Real answers, two valid and one refused:

Asked	Got	So
“Make me a chart about how things are going.”	valid · `chart@6baf09f0` a line chart of five weeks of counts	Captured before the API refused such requests by default: Forma made the numbers up. Today the API refuses it with DATA_REQUIRED, unbilled, unless generated data is allowed, as the console allows it.
“Make me a chart about how things are going.”	refused · `DATA_REQUIRED` “This chart needs values the request does not contain. Put them in the intent, or set allow_generated_data to true for illustrative values.” HTTP 422, not billed · 2026-10-07	The same request today, sent to the API with its default setting: a plain no and the reason, instead of numbers Forma made up.
“Points A at (0,0), B at (4,0) and C at (2,1). Draw segment AB and point C, and check that A, B and C are collinear.”	valid · `vector-graphics@c738bf88` C drawn on AB, not above it	The check holds in the figure returned, but Forma moved a coordinate you gave it to make it hold. Read the source before trusting the picture.

per call

$0.01

billed

valid · invalid

never billed

error

credits

never expire

05 Start

Start in the browser, or from your agent.

Free plan: 20 calls a month, every product, every format. Try it in the console, or connect your agent with one line and sign in when it asks.

Try it free Pricing

Claude Code

claude mcp add --transport http forma https://mcp.formalogic.io/mcp

Other clients and the HTTP API