Document chart capability gaps

[Alek99]

Summary

• add a normative capability-gap contract covering 50 charting gaps found against Matplotlib, Plotly, Seaborn, Altair, and Bokeh
• explicitly mark every gap as NOT IMPLEMENTED, including distinctions for partial support and prototypes
• define acceptance criteria, priorities, milestones, and evidence required before any capability can be called implemented
• align the chart roadmap, spec index, and production-readiness guidance with those status rules

Why

The existing specs could be read as conflating stable declarative support with pyplot-only paths, prototypes, partial implementations, or roadmap intent. This update makes the remaining product gaps unambiguous and prevents planned work from being represented as shipped functionality.

Impact

Spec-only change. No runtime behavior or public API implementation is added by this PR.

Future rows may move to Implemented only when the implementation, tests, public documentation, host coverage, and relevant export coverage land together.

Validation

• make check-docs — 55 passed, 2 skipped; both repository documentation checks passed
• structural audit — exactly 50 unique capability IDs, every row explicitly marked NOT IMPLEMENTED, all local Markdown links resolved, and table structures validated
• external comparison links checked
• git diff --check

[greptile-apps]

Greptile Summary

This PR documents the remaining chart capability gaps and defines when they may be considered implemented. The main changes are:

• A normative 50-item capability-gap contract.
• Clear separation between declarative and pyplot-only chart support.
• Acceptance criteria, priorities, milestones, and evidence requirements.
• Links from the spec index and production-readiness guidance.

Confidence Score: 4/5

The production-readiness claim rule needs a narrow wording fix before merging.

The chart classifications match the documented public surfaces. The new contract consistently labels its gap rows. The claim rule currently conflicts with existing safe claims and the preserved shipped baseline.

spec/process/production-readiness.md

T-Rex Logs

What T-Rex did

• Before state was validated: the parent revision passed documentation checks and the capability-gap contract was absent as expected.
• After state was validated: documentation checks passed and the new contract passed its deterministic structural audit.
• Confirmed that no finding was created for the explicitly excluded accepted production-readiness issue.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
spec/api/capability-gap-contract.md	Adds the normative capability inventory, status rules, milestones, and implementation evidence requirements.
spec/api/chart-roadmap.md	Clarifies which chart families are declarative and which remain available only through the pyplot shim.
spec/process/production-readiness.md	Links claims to the new contract, but applies the empty Implemented-row set too broadly.
spec/README.md	Adds the capability-gap contract to the specification index.

_{Reviews (1): Last reviewed commit: "Document chart capability gaps" | Re-trigger Greptile}

[greptile-apps]

Empty Implemented Set Blocks Valid Claims

Every capability row in the linked contract is currently marked NOT IMPLEMENTED, so this unqualified rule makes an empty set the limit for all product claims. A maintainer applying it literally must remove the existing safe benchmark and shipped-baseline claims, even though the contract says those shipped primitives are not downgraded. Scope this rule to capabilities represented by the gap rows.

Suggested change

	Claims must not outrun the rows marked **Implemented** there.
	Claims about capabilities represented in that backlog must not outrun the rows marked **Implemented** there.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[codspeed-hq]

Merging this PR will not alter performance

✅ 97 untouched benchmarks
⏩ 1 skipped benchmark¹

---

_{Comparing agent/document-chart-capability-gaps (895a51c) with main (517727e)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩