Chart Generation

Chart Generation Skill

Produce accurate, source-grounded charts from researched or computed data. This skill has two delivery modes; choose the one that matches the tools you were given, then follow the matching section below.

Choose your mode

1. Sandbox mode (an execute tool is available): render a PNG with Python/matplotlib, save it as a durable artifact, and embed it by reference. Follow Sandbox Mode (PNG artifact) below.
2. Inline mode (no execute tool / no sandbox): emit the chart as an inline fenced chart JSON spec that the web app renders, plus a portable Markdown table. Follow Inline Mode (chart spec) below. Do NOT attempt to run code or produce a PNG.

The two modes are mutually exclusive and are selected only by tool availability: pick exactly one and emit only that output path. When an execute tool (sandbox) is available you must use Sandbox mode and must not emit an inline chart spec; only when no execute tool exists do you use Inline mode. Never produce both a PNG artifact and an inline spec for the same figure.

Both modes share the same discipline: a chart confers authority, so it must be earned.

Data sufficiency (earn the chart, both modes)

A polished chart of wrong or sparse numbers misleads more than it informs.

1. Source-anchored points only: every plotted value must trace to a specific source (the as-reported figure and its URL). Never plot a fabricated, guessed, or inferred number as if it were reported; mark genuine estimates as estimates.
2. Suppress misleading charts: if a series is mostly missing (a majority of periods undisclosed) or mixes metric definitions (e.g. "cash capex" vs "capex including finance leases"), do NOT produce a trend chart. Present the table (which shows the gaps) and state the limitation in one sentence instead.
3. Show gaps honestly: never interpolate or connect across missing periods. Plot only the periods a series actually reports, and render estimates distinctly so they do not read as reported values.
4. Prefer gap-tolerant forms: grouped bars show missing periods as absent bars; favor them over a connected line when series are uneven, since a line drawn across gaps implies a trend the data does not support.
5. Use the ACTUAL numbers from the evidence (top ~10 rows); never invent, pad, or round away data. If you show only the top rows of a larger set, say so.

Sandbox Mode (PNG artifact)

Render with Python/matplotlib, save the chart as a durable artifact, and embed it in the report by reference (never by pasting image data).

Required Execution Standard

1. Ground the data: build the plotted rows from researched facts or /shared/... inputs. Keep source URLs/notes alongside the values.
2. Normalize units before plotting (currencies, magnitudes, periods).
3. Render with code: call execute to run Python/matplotlib. Do not hand-draw or fabricate charts.
4. Write to the artifact directory: save the PNG and its CSV under the exact sandbox_artifact_dir given in your instructions (a per-job path such as /sandbox/<job_id>/aiq-artifacts). Use that value verbatim - do NOT write to a bare /sandbox/aiq-artifacts; the runtime only harvests files under sandbox_artifact_dir.
5. Write a manifest to carry the chart's title, caption, and inline flag and to checkpoint it mid-run (see below). It is preferred, not strictly required: a chart left in sandbox_artifact_dir is still captured by the terminal directory scan without one.
6. Reference, do not embed bytes: in the report, link the chart with ![caption](artifact://<filename>.png). The runtime resolves this to the durable artifact; never paste base64 image data into the report.

Execution Flow

1. Assemble the normalized rows (prefer explicit records embedded in the script). If the inputs live in /shared/..., read_file them first and embed the values; sandbox code cannot open /shared/....
2. Use write_file to create the chart script under the exact sandbox_workdir from your instructions, then execute it with the exact sandbox_artifact_dir as its first argument. For example, when your instructions provide /sandbox/JOB/ and /sandbox/JOB/aiq-artifacts, run python3 /sandbox/JOB/make_chart.py /sandbox/JOB/aiq-artifacts. Never execute a literal <sandbox_workdir> or <sandbox_artifact_dir> token. sandbox_workdir is already per-job, so scripts there cannot collide with another job's leftovers. Only ever execute a script you wrote this session. Each execute runs in a fresh shell, so cd does NOT persist between calls; put absolute paths in every command (or chain in one line as cd <dir> && <cmd>). The script must:
   • import pandas and matplotlib (use the non-interactive Agg backend),
   • build the DataFrame, compute any derived metrics,
   • set a single ARTIFACT_DIR to your sandbox_artifact_dir and write the chart (<name>.png), its data (<name>.csv), and manifest.json there (see the example).
3. Inspect the execute output; if it fails, fix the script and re-run (max 2 retries).
4. In the report, embed the chart with ![<caption>](artifact://<name>.png) and cite the original data sources in the surrounding text.

Placement and description in the report

Each figure must appear where it is discussed, not buried in a file list:

1. Embed once, in context: place the ![<caption>](artifact://<name>.png) line inside the section that analyzes the figure (e.g. Results, Findings, or a Visualization subsection) - immediately after the paragraph that introduces it.
2. Describe it: precede the embed with one sentence stating what the chart shows and the takeaway (e.g. "The chart below compares 2025 resident population across the top five states; California leads at roughly 3x Pennsylvania.").
3. Reference by filename, never a raw path: the way to show a figure is the ![caption](artifact://<filename>.png) token. Do NOT instead write the sandbox path (e.g. <sandbox_artifact_dir>/<name>.png) as prose and expect it to render - a bare path is not an image. Never paste the plotting code or base64 image data into the report; do not read_file a generated PNG just to verify it (that injects base64 bytes into context).
4. One embed per artifact: list supporting files (CSVs, manifests) by name in an appendix if useful, but the chart itself must be embedded inline as above.

Manifest

Write a manifest.json in your sandbox_artifact_dir so the runtime captures the chart with its metadata. The manifest is the preferred path, not a hard requirement: a successful execute checkpoints the manifest-declared artifacts immediately, and the manifest carries the title, caption, and inline flag that let the chart render inline with a caption. If no valid manifest is written, the terminal directory scan still captures any file left in sandbox_artifact_dir as a successful fallback, but with default metadata (no title or caption, and not auto-inlined), so the manifest is how you get an inline, captioned chart. Manifest path values must be absolute and inside your sandbox_artifact_dir (the per-job path from your instructions). Construct every manifest path from the runtime argument as shown below; do not hand-copy an angle-bracket placeholder into JSON. Set inline: true only for a raster image intended to appear in the report.

Example Script

import json
import sys
from pathlib import Path

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import pandas as pd

if len(sys.argv) != 2:
    raise SystemExit("usage: make_chart.py ABSOLUTE_SANDBOX_ARTIFACT_DIR")
ARTIFACT_DIR = Path(sys.argv[1])
if not ARTIFACT_DIR.is_absolute():
    raise SystemExit("artifact directory must be an absolute path")
ARTIFACT_DIR.mkdir(parents=True, exist_ok=True)

rows = [
    {"company": "ExampleCo", "revenue_usd_billions": 12.4, "source": "https://example.com/filing"},
    {"company": "SampleInc", "revenue_usd_billions": 9.1, "source": "https://example.com/10k"},
]
df = pd.DataFrame(rows).sort_values("revenue_usd_billions", ascending=False)

fig, ax = plt.subplots(figsize=(8, 5))
ax.bar(df["company"], df["revenue_usd_billions"])
ax.set_ylabel("Revenue (USD billions)")
ax.set_title("2024 Revenue Comparison")
fig.tight_layout()

png_path = ARTIFACT_DIR / "revenue_chart.png"
csv_path = ARTIFACT_DIR / "revenue_chart.csv"
fig.savefig(png_path, dpi=150)
df.to_csv(csv_path, index=False)

manifest = {
    "version": 1,
    "artifacts": [
        {
            "path": str(png_path),
            "kind": "image",
            "title": "2024 Revenue Comparison",
            "caption": "Revenue normalized to USD billions.",
            "inline": True,
            "source_files": [r["source"] for r in rows],
        }
    ],
}
with (ARTIFACT_DIR / "manifest.json").open("w", encoding="utf-8") as handle:
    json.dump(manifest, handle)

print(f"wrote {png_path}")

Run the script with the two exact per-job paths given in your instructions. The second argument must be the real absolute artifact directory, not an angle-bracket placeholder. Treat the artifact-checkpoint response after execute as authoritative: reference the exact confirmed filename in the report and do not invent or rename it later.

Sandbox notes and limitations

• Use the Agg backend; the sandbox has no display.
• Keep charts legible: labeled axes, a title, and a legend when multiple series are shown.
• Do not call read_file on the generated PNG merely to verify it; binary reads return base64 and waste model context. Inspect manifest.json with read_file(file_path=...) when needed, then rely on the artifact-checkpoint response to confirm the accepted filename and inline state.
• If matplotlib or pandas is unavailable, report that the sandbox image needs them rather than fabricating a chart.
• Reference charts only by artifact://<filename>; the runtime assigns the durable id and rewrites the reference for the UI, PDF export, and the packaged skill CLI.

Inline Mode (chart spec)

When there is no execute tool, present numbers that compare multiple things (a ranking or top-N across entities, a distribution or counts across categories, a trend over an ordered/time axis, or gains vs losses) as an inline chart, not just prose or a table. Lead with a one-sentence verdict, then the chart.

• Emit the chart as a fenced code block tagged chart holding a SINGLE line of valid JSON (no comments, no trailing commas), right after the sentence that introduces it.
• Chart to reveal the pattern and state the verdict in prose. Inline chart blocks render only in the web app, so ALSO place a compact markdown table of the same values immediately after each chart, keeping PDF, Markdown, API, and CLI exports readable.
• At most 3 charts per section, and put each chart before any table.
• A single value or a one-entity yes/no result is NOT a chart: emit a KPI-only block, a fenced chart block whose JSON has just title and kpis.

Chart types: bar (category magnitudes), hbar (rankings with long text labels), line/area (a trend across an ordered axis), grouped-bar (2-4 series per category), delta (gains vs losses around zero).

Spec fields: type; title (short) and optional subtitle; x = { "key": "<field in each row>", "label": "optional" }; optional y = { "label": "optional unit", "format": "number | compact | percent | currency" }; series = [ { "key": "<numeric field>", "label": "optional", "color": "green | blue | amber | red" } ]; data = rows as objects with raw numbers (fractions 0-1 for percent); optional kpis = [ { "label": "...", "value": "preformatted", "tone": "accent | warn | alarm" } ]. A delta chart encodes exactly one series.

Example (ranking):

{"type":"hbar","title":"Top suppliers by late shipments","x":{"key":"supplier"},"y":{"format":"number"},"series":[{"key":"late","color":"amber"}],"data":[{"supplier":"Acme","late":42},{"supplier":"Globex","late":31},{"supplier":"Initech","late":19}]}

Example (single value, KPI-only):

{"title":"On-time delivery rate","kpis":[{"label":"On-time","value":"92.4%","tone":"accent"}]}

For several related trends over time, emit one fenced chart-carousel block holding a SINGLE line of JSON with at least two line-chart specs: { "title": "...", "charts": [ <line chart spec>, ... ] }.

Example (related trends, carousel):

{"title":"Quarterly delivery trends","charts":[{"type":"line","title":"On-time delivery rate","x":{"key":"quarter"},"y":{"format":"percent"},"series":[{"key":"rate","color":"green"}],"data":[{"quarter":"Q1","rate":0.88},{"quarter":"Q2","rate":0.90},{"quarter":"Q3","rate":0.93}]},{"type":"line","title":"Late shipments","x":{"key":"quarter"},"y":{"format":"number"},"series":[{"key":"late","color":"amber"}],"data":[{"quarter":"Q1","late":52},{"quarter":"Q2","late":41},{"quarter":"Q3","late":28}]}]}