> ## Documentation Index > Fetch the complete documentation index at: https://docs.bluprynt.com/llms.txt > Use this file to discover all available pages before exploring further. # How change detection works > How Disclosure Monitoring re-reads sources, versions them, classifies each change for materiality and gates removals on evidence. Disclosure Monitoring treats a change as a difference between two versions it actually held. It re-reads each tracked source on a cadence, keeps every version with its hash, and classifies each difference so you only get paged for what matters. This page explains each step and the rules it holds itself to. ## Key concepts | Term | Meaning | | - | - | | Tracked source | An issuer page, terms, attestation, filing or register that the registry already holds for the asset | | Re-read | One fetch of a tracked source on its cadence | | Version | One held copy of a source, identified by the SHA-256 hash of its normalized text | | Change | A difference between two held versions in a disclosed field, register status, sanctions result, named party or collateral link | | Materiality | The class a change is given: **Material**, **Clarification**, **Editorial**, **Needs review** or **Unclassified** | | Draft | A change whose old or new wording couldn't be held, or whose materiality is still under review. Drafts are never notified. | | Evidence-gated removal | A field that vanishes is re-read several times before it counts as removed. | ## How it works ```mermaid theme={"system"} flowchart TD A[Re-read source] --> B[Normalize text] B --> C[Hash with SHA-256] C --> D{New hash?} D -->|No| A D -->|Yes| E[Compare fields] E --> F[Classify materiality] F --> G{Confirmed?} G -->|Yes| H[Notify watchers] G -->|No| I[Keep as draft] ``` 1. **Re-read.** Every tracked source is fetched again on a schedule. Register, sanctions, named-party and collateral monitors run on their own cadence. 2. **Normalize and hash.** The text is normalized before it is hashed with SHA-256, so a re-rendered page or reflowed PDF stays one version. 3. **Compare.** Only text that was actually read on both sides becomes a change. A different value, a removed statement or two sources that disagree is a change. Reflowed layout or a renamed heading is not. 4. **Classify.** Each change is classified for materiality. 5. **Confirm.** A confirmed change is notified. A draft waits and doesn't count until it is confirmed. ## Follow a field through four re-reads The first time a source is read, the value is recorded as the **first reading** (1). Here the `reserve_custodian` field reads **BNY Mellon**. A timeline for the reserve_custodian field with callouts on the first reading, an editorial reflow, a clarification to the same party and a new custodian marked as material. In March the PDF is re-rendered. The value is the same, so the change is **Editorial · reflowed PDF** (2) and is folded away. In May the document names **The Bank of New York Mellon**. It is the same party with a better name, so the change is a **Clarification · same party** (3). It stays on the timeline without paging anyone. In August the custodian becomes **State Street Bank**. A new custodian is **Material** (4). It is the event a compliance desk sees first, with before, after and the quote. A field that vanishes is re-read several times before it counts as removed (1). Monitoring doesn't alert on every byte that moves, doesn't pick a winner when two sources disagree and doesn't treat a failed fetch as a withdrawn disclosure (2). The Disclosure Monitoring rules with callouts on the evidence-gated removal rule and the list of things it will not do. ## Reference ### Materiality classes | Class | Label | Meaning | Notified? | | - | - | - | - | | `material` | **Material** | A disclosed fact changed | Yes | | `clarification` | **Clarification** | Same fact, more precise | If you chose **Material + clarifications** or **Everything** | | `editorial` | **Editorial** | Wording only, folded away | If you chose **Everything** | | `review` | **Needs review** | Needs an analyst | — | | `unclassified` | **Unclassified** | Not yet classified | — | ### Confirmation states | State | Meaning | | - | - | | **Confirmed** | The change is confirmed and counts. | | **Candidate · not confirmed** | The change was detected but isn't confirmed yet. | | **Draft · awaiting classification** | The change is waiting for its materiality. It is shown dashed and isn't notified. | ### Change headlines | Headline | When | | - | - | | **Newly disclosed** | A field had no value and now has one | | **Disclosure changed** | A field's value changed | | **Disclosure withdrawn** | A field's value was removed, after the evidence gate | | **Sources disagree** | Two sources state different values for the same field | | **Source document changed** | A tracked document changed in substance | | **Licence or register status changed** | A register entry changed | | **Sanctions screening match** | Screening returned a match | | **Named party changed** | A named party changed | | **Collateral linked** | A collateral ISIN was linked | ### Cadence and freshness | Item | Value | | - | - | | Default re-read cadence | Daily (`P1D`) | | Due | A source is due once 36 hours pass without a check | | Monitor run | **Current**, **Stale** or **No run recorded** | | Source read state | **Read**, **Pending** or **Unreadable** | ### Rules | Rule | What it means for you | | - | - | | Same source, same field | Two sources disagreeing is a finding, not a change. Both values are recorded and flagged. | | Removal is evidence-gated | A field that vanishes is re-read several times before it counts as removed. A failed fetch is never a withdrawal. | | History is immutable | Every value ever read stays retrievable with the document that produced it. | | Noise is folded, not dropped | Editorial revisions collapse in the timeline, so they never hide a material one. | | What can't be read is said, not scored | An unreadable or paywalled source is listed as unreadable. | ## Worked example: a reserve attestation changes firm An issuer's monthly attestation used to say "Monthly attestation by Firm A LLP". The next re-read finds "Monthly attestation by Firm B LLP". 1. The new text hashes differently, so it is a new version. 2. The attester field changed value, so it is a **Disclosure changed** event. 3. A different firm is a different fact, so it is **Material**. 4. Once confirmed, everyone watching the asset gets a notification, whatever their preference. 5. The change detail shows both quotes, the source, both SHA-256 hashes and the change ID. ## Errors and limits | Situation | What happens | | - | - | | A source can't be fetched | The source is marked unreadable. Nothing is treated as withdrawn. | | A source is paywalled | It is listed as unreadable rather than scored. | | No sources are tracked for an asset | Coverage reads **No sources**. A quiet feed doesn't mean nothing changed. | | Wording couldn't be held on one side | The change stays a draft and isn't notified. | ## FAQ Text is normalized before it is hashed, so a reflowed PDF stays one version. If the wording changed but the meaning didn't, the change is **Editorial** and folded away. Monitoring records both values and flags the disagreement. It doesn't pick a winner. No. A failed fetch is never treated as a withdrawn disclosure, and a removal needs several re-reads first. ## Related pages Read a change with its proof. Choose what to be notified about. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.