Date Comparison
Show how this period compares with the last one.
What it adds
Period-over-period comparison on analytics figures, with aligned periods, honest handling of incomplete ranges, and sane percentage changes.
What your agent is told to do
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What your agent is told to do
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Offer previous period and same period last year as comparison options, and allow a custom comparison range.
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Make the comparison period exactly the same length as the selected period, and state the compared dates in the UI. An unexplained percentage is not information.
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When the current period is still running, compare like for like — either compare elapsed portions only, or label the figure as partial. Do not compare four days against thirty and call it a decline.
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Do all bucketing and boundary arithmetic in the reporting time zone, and show which time zone that is.
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Show direction with more than colour: an arrow or a sign, so the change is readable to colourblind users and in monochrome print.
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Do NOT build a new range-selection control — the picker is owned by Date Range Picker; read the selected range from it and extend that feature if it needs a comparison mode.
Edge cases it handles
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Edge cases it handles
7- A zero baseline has no percentage change. Show 'no prior data' or the absolute figure, never infinity or a 100% that means nothing.
- A tiny baseline produces absurd percentages — two to six is +200%. Suppress or annotate changes below a minimum sample.
- Month-over-month comparison across months of different lengths must either align by day count or say it is aligning by calendar month.
- Leap days and daylight-saving transitions make some periods 23 or 25 hours long; bucket boundaries must not drift.
- Same period last year should align by weekday for weekly-seasonal metrics, or the comparison is noise.
- Rate metrics do not subtract like counts — a change in conversion rate is percentage points, not percent.
- Late-arriving data will change yesterday's number after you have already shown a comparison; either wait for the data to settle or label recent figures as provisional.
Definition of done
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Definition of done
9- Every comparison states both date ranges explicitly.
- Comparison periods are equal in length to the selected period.
- Incomplete current periods are either elapsed-matched or clearly labelled as partial.
- All boundaries are computed in a stated reporting time zone.
- Zero and near-zero baselines never produce a misleading percentage.
- Direction is conveyed by more than colour alone.
- Range selection continues to be handled by Date Range Picker.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
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Give every tracked interaction a name that still means the same thing in a year.
What it does
A documented vocabulary and structure for event names and properties, applied across the app's existing tracking.
How it works
- 1 Audit the events the app already sends and list them. The duplicates, the near-synonyms, and the ones nobody can explain are the reason the schema is needed, and they are also the migration list.
- 2 Fix a structure of object, action, and context: what was acted on, what happened to it, and where. Fix a closed set of actions — viewed, clicked, opened, submitted, selected, failed — and require every new event to reuse one of them.
- 3 Keep variable detail in properties, never in the name. A record identifier, a plan name, or a workspace slug baked into an event name produces thousands of unaggregatable one-off events.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/ui-event-naming-schema
Data Table Cell Primitives
Data Table Cell Primitives
Render every kind of table cell the same way, wherever the table happens to be.
What it does
A shared set of cell renderers for numbers, dates, people, statuses, links, and row actions, used by every table in the app.
How it works
- 1 Catalogue the cell types the app's tables already render and reduce them to a small set: number and currency, date and relative time, person or avatar, status or badge, link or identifier, and an actions cell.
- 2 Separate each cell's underlying value from its presentation, so sorting, filtering, grouping, and export operate on the raw value while the user sees the formatted one.
- 3 Align and format numerically consistent cells the same way everywhere — figures right-aligned with tabular figures and a fixed precision per column, dates in the user's locale and time zone, currency with its code where more than one is possible.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/data-table-cell-primitives
Segment Event Forwarding
Segment Event Forwarding
Send one clean stream of product events to Segment and let it fan out downstream.
What it does
A documented event schema and a single forwarding path emitting track, identify, group, and page calls with consistent identity.
How it works
- 1 Write the event schema before writing any code: the exact set of event names, the properties each carries with their types, and the traits attached to a user and to an account. Every downstream tool inherits this schema, so a name chosen carelessly is expensive to change later.
- 2 Establish one identity model and apply it everywhere. Use a stable internal user identifier that never changes, associate the anonymous identifier from the first visit with it at signup, and attach the account or workspace so downstream tools can roll events up by customer.
- 3 Route every event through one internal emitter rather than calling the provider from feature code. That emitter validates the event against the schema, drops or flags anything unrecognised, and is the single place where identity and default properties are attached.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/segment-event-forwarding
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.