# AGENTS.md — Build guide for Snappa ## Project scope Compose a fixed-size social graphic from local images, headline text and a few reusable layouts, then export exact-size PNG/SVG. Catalogue verdict: yes. The core loop is small enough for a capable coding agent to produce a useful local version in one sitting. For Snappa, compose fixed-size social graphics from local images, text, and a small template set. The hard boundary is stock-photo allowance, templates, team sharing, and cloud convenience, plus editor polish, assets, collaboration, and distribution. Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope. ## Working agreement - Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture. - Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled. - After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran. - Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply. - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization. ## Prerequisites - Runtime and tools: TypeScript, React, SVG or Canvas and IndexedDB with a versioned JSON project format. - Before starting: A browser with IndexedDB, licensed example assets and fonts, and an agreed output size. ## Stack and architecture - TypeScript, React, SVG or Canvas and IndexedDB with a versioned JSON project format - Data design: Store Template, Placeholder, ImageTransform, TextStyle and Design; placeholders enforce visible overflow warnings and exports preserve declared dimensions. - Setup: A browser with IndexedDB, licensed example assets and fonts, and an agreed output size ## Security and data integrity - Maintain one document model for preview, undo and export. Use stable element IDs; save after completed gestures, handle storage quota errors and provide explicit file backups. - Keep templates small and licensed. Stock imagery and font rights are not included automatically, and resizing is a reviewed layout change rather than a promise of perfect one-click adaptation. - Keep secrets outside client bundles and exported projects; document what leaves the device and make retention/deletion controls visible. ## Agent implementation rules - Project rule — domain: Store Template, Placeholder, ImageTransform, TextStyle and Design; placeholders enforce visible overflow warnings and exports preserve declared dimensions. - Project rule — scope and recovery: Keep templates small and licensed. Stock imagery and font rights are not included automatically, and resizing is a reviewed layout change rather than a promise of perfect one-click adaptation. - Project rule — acceptance: Replace a short headline with a long one and use a transparent logo; show the overflow before export and preserve transparency without a hidden background layer. - Project rule — delivery: document real setup commands and permissions; do not claim a build, accuracy level, performance result or security certification that has not been demonstrated. ## Optional agent skills and references - Recommended skill: [vercel-composition-patterns](https://github.com/vercel-labs/agent-skills/blob/main/skills/composition-patterns/SKILL.md) — separate document tools, property inspectors and export controls into explicit reusable React components. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. - Recommended skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — review keyboard access, focus, validation, error recovery and the readable work/review interface or HTML report. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism. ## Distribution ideas These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone. - Demonstrate this working slice using synthetic or explicitly authorized non-sensitive examples: Compose a fixed-size social graphic from local images, headline text and a few reusable layouts, then export exact-size PNG/SVG. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Replace a short headline with a long one and use a transparent logo; show the overflow before export and preserve transparency without a hidden background layer. - State the limits before asking someone to replace their existing tool: Keep templates small and licensed. Stock imagery and font rights are not included automatically, and resizing is a reviewed layout change rather than a promise of perfect one-click adaptation. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Compose a fixed-size social graphic from local images, headline text and a few reusable layouts, then export exact-size PNG/SVG. Confirm setup: A browser with IndexedDB, licensed example assets and fonts, and an agreed output size. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store Template, Placeholder, ImageTransform, TextStyle and Design; placeholders enforce visible overflow warnings and exports preserve declared dimensions. 3. Phase 3 — Connect the working view to real saved state. Maintain one document model for preview, undo and export. Use stable element IDs; save after completed gestures, handle storage quota errors and provide explicit file backups. 4. Phase 4 — Expose the app-specific limits and recovery path in context: Keep templates small and licensed. Stock imagery and font rights are not included automatically, and resizing is a reviewed layout change rather than a promise of perfect one-click adaptation. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Replace a short headline with a long one and use a transparent logo; show the overflow before export and preserve transparency without a hidden background layer. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - stock-photo allowance, templates, team sharing, and cloud convenience - huge template and asset libraries - real-time multiplayer - brand governance - professional print workflows ## Implementation prompt Build the following focused alternative to Snappa. Implement the focused workflow below first; the verdict is not evidence of a completed or production-certified build. WORKING SLICE Compose a fixed-size social graphic from local images, headline text and a few reusable layouts, then export exact-size PNG/SVG. SETUP AND ARCHITECTURE Use TypeScript, React, SVG or Canvas and IndexedDB with a versioned JSON project format. Prerequisites: A browser with IndexedDB, licensed example assets and fonts, and an agreed output size. Before integrating anything, record actual versions and permissions, plus model files or provider limits only where used, in the README; make unavailable dependencies visible rather than simulating success. DOMAIN MODEL AND INVARIANTS Store Template, Placeholder, ImageTransform, TextStyle and Design; placeholders enforce visible overflow warnings and exports preserve declared dimensions. IMPLEMENTATION CONTRACT Maintain one document model for preview, undo and export. Use stable element IDs; save after completed gestures, handle storage quota errors and provide explicit file backups. Provide an input/setup view, the main work view, and a review/export view appropriate to this workflow. Preserve the last saved state if a job or save fails. Include empty, loading, permission-denied, partial and retryable-error states. Log identifiers and error categories without secret values or unnecessary private content. APP-SPECIFIC BOUNDARY AND RECOVERY Keep templates small and licensed. Stock imagery and font rights are not included automatically, and resizing is a reviewed layout change rather than a promise of perfect one-click adaptation. ACCEPTANCE SCENARIO Replace a short headline with a long one and use a transparent logo; show the overflow before export and preserve transparency without a hidden background layer. Also reopen the app after an interrupted operation, confirm the saved record/export remains inspectable, and document the recovery action. These are implementation acceptance requirements, not a claim that this guide has been tested. DELIVERY Deliver a runnable repository with migrations or project-format versioning, a non-sensitive example, environment/permission setup, the exact manual acceptance steps, and a backup/export-and-restore walkthrough. Implement the working slice before optional integrations; list any deferred paid-product capabilities honestly. Do not add capabilities outside the working slice just to resemble the original product. PROJECT RULES FOR AGENTS.md Keep the domain invariants above executable at the write boundary. Propose scope changes before adding providers or permissions. Never fabricate source evidence, publish results, identity matches or successful delivery. Preserve user originals and require an explicit confirmation for destructive changes or external publication. ## Completion evidence Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.