# `Excessibility.MCP.Tools.DiffSnapshots`
[🔗](https://github.com/lessthanseventy/excessibility/blob/v0.18.1/lib/excessibility/mcp/tools/diff_snapshots.ex#L1)

MCP tool: diff two rendered HTML states and report what changed and
whether the change introduced accessibility regressions.

Lets an agent that just edited a LiveView ask *"did I change rendered
behavior I didn't intend?"* It returns the changed regions plus any
newly-introduced accessibility findings — content that updated without an
`aria-live` announcement, a control made keyboard-inaccessible, and so on
— and a risk tier (`auto`/`review`/`block`). Backed by
`Excessibility.Review`.

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*Consult [api-reference.md](api-reference.md) for complete listing*