International Standard Serial Number
Enable an AI agent to recognise an ISSN, verify its assignment to a continuing resource, and decide whether to use it, investigate a mismatch or request an authoritative correction.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex
Purpose and description
Enable an AI agent to recognise an ISSN, verify its assignment to a continuing resource, and decide whether to use it, investigate a mismatch or request an authoritative correction.
It can be Normalise an observed ISSN and validate its check digit while preserving the original evidence; Look up an assignment and compare its key title and medium with the claimed publication; Match catalogue records at the identified resource and medium level; Group medium versions through a verified ISSN-L association; Follow documented title relationships to retrieve earlier or later publications; Prepare an assignment or correction request for the responsible ISSN centre when evidence requires authoritative action.
Distinguishing features
An ISSN has eight positions: seven digits and a final check character that can be a digit or X; passing the modulus-11 check establishes structural validity, not assignment. [ISSN explanation](https://www.issn.org/understanding-the-issn/what-is-an-issn/)
Its referent is a continuing resource, rather than a particular article or issue; the model must establish that resource boundary before using the identifier.
An ISSN identifies a medium version; an ISSN-L has the distinct role of grouping medium versions, even when its characters equal one member ISSN. [ISSN-L guidance](https://www.issn.org/understanding-the-issn/assignment-rules/the-issn-l-for-publications-on-multiple-media/)
An authoritative assignment connects the identifier to a key title, which can include qualifiers distinguishing otherwise identical publication titles. [Key-title explanation](https://www.issn.org/faq/what-is-an-issn/)
The code does not encode publication origin or content, and possession of an ISSN does not establish content quality. [ISSN explanation](https://www.issn.org/understanding-the-issn/what-is-an-issn/)
Scope
+ ISSN syntax, canonical presentation and check-digit validation
+ Evidence connecting an ISSN to an authoritative assignment record
+ The identified continuing resource, its key title and medium
+ Assignment history, conflicting assertions and correction needs
+ Relationships to ISSN-L, other medium versions and preceding or succeeding titles
+ Conditions for using the ISSN in matching, citation and catalogue workflows
- Editorial content, scholarly quality and reputation of the identified publication
- Individual articles, issues, volumes and their separate identifiers
- Publisher organisations, ownership and contractual rights
- Subscription products, holdings, licences and access entitlements
- Hosting platforms, URLs and digital preservation infrastructure
- Administration of the ISSN Network as an organisation
Characteristics
- Observed and canonical expression
- Original observed string; canonical NNNN-NNNC expression, where N is a digit and C is a digit or X Supports comparison while preserving evidence of transcription or display errors.
- Structural validation result
- Unchecked; malformed; check-digit failure; structurally valid Prevents a plausible-looking string from being accepted without basic validation.
- Assignment verification
- Unverified; authority-confirmed; conflicting evidence; unresolved after lookup Separates an algorithmically valid number from a supported assignment.
- Identified resource
- Continuing resource linked through its authoritative key title and assignment record Establishes what the number actually identifies.
- Assigned medium
- Medium recorded by the authority, such as print or online; unknown if unverified Prevents conflating different medium versions of a publication.
- Authority-recorded identifier status
- Exact status supplied by the consulted authority, or unknown Keeps authoritative status distinct from local validation and publication activity.
- ISSN-L association
- Authority-supported linking ISSN and associated medium versions; unresolved if unsupported Permits grouping versions without treating their identifiers as interchangeable.
- Title continuity relationships
- Documented predecessor, successor, merger, split or other title relationships Supports historical retrieval without collapsing distinct assignments.
- Verification age
- Elapsed days since the supporting assignment record was checked Helps decide whether a consequential use requires another authority lookup.
- Observed use alignment
- Matches assigned resource and medium; resource mismatch; medium mismatch; unresolved Detects a real ISSN displayed on the wrong publication or version.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 10 layers · 10 findings · 27 questions.
ISSN expression Recognise the identifier in text and test its structural integrity.
A transcription error must be distinguished from a valid number used for the wrong resource.
Observed expression
Preserve how and where the candidate identifier appeared.
Canonical ISSN
Record the original string, its surrounding label and any unambiguous formatting normalisation.
- What exact characters and ISSN or ISSN-L label were observed? provenance
- Can the expression be normalised without guessing missing or ambiguous characters? action
Check-digit validation
Evaluate structural validity independently of assignment evidence.
Structural test result
Record whether the candidate passes the format and modulus-11 checks without silently repairing it.
- Does the candidate have seven initial digits and an allowed final check character? measurement
- Does the calculated check character match the observed final character? measurement
- If validation fails, what source must be checked before proposing a correction? action
Assignment evidence Establish whether the number has a supported ISSN assignment.
Checksum validity and publisher display alone cannot settle authoritative assignment.
Authority record
Connect the candidate to an inspected ISSN authority record.
Verified assignment
Record the consulted authority, record reference, access date and evidence actually available.
- Which inspected ISSN Network record or assignment communication supports this number? provenance
- Which assignment details were visible, and which remain inaccessible or unverified? boundary
Assignment discrepancies
Keep identifier status and conflicting claims explicit.
Status and conflict
Preserve authority-supplied status separately from local conclusions and secondary-source assertions.
- What identifier status does the authority explicitly report? provenance
- Do publisher pages or catalogues assert a different assignment, and what evidence could resolve the conflict? provenance
- Does an unsuccessful lookup leave the assignment unresolved rather than establish that it never existed? boundary
Identified resource boundary Determine the continuing resource and medium to which the assignment applies.
Title similarity can conceal different resources, and a correct ISSN can be attached to the wrong medium.
Key-title identity
Relate the observed publication name to its authoritative identifying title.
Title correspondence
Record the key title, relevant qualifiers and evidence connecting displayed or variant titles to it.
- What key title and qualifiers accompany this ISSN in the authority record? definition
- What evidence shows that the observed publication is this resource rather than another with a similar title? boundary
Medium and resource level
Locate the assignment at the appropriate publication level and medium.
Referent fit
Test whether the claimed use concerns the assigned continuing resource and version.
- Which medium does the assignment record identify, and does the observed resource match it? boundary
- Is the agent identifying the continuing resource, an individual issue or an article? definition
- If the number appears on another format or edition, what authority evidence supports that use? provenance
Linking and title history Represent related medium versions and changes in publication identity.
Agents need to distinguish grouping related resources from asserting that they share one assignment.
ISSN-L grouping
Represent the designated linking identifier and supported version membership.
Medium-version links
Keep the medium-specific ISSN role separate from the ISSN-L role.
- Which ISSN-L is authoritatively associated with this ISSN? provenance
- Does the proposed operation need one medium version or the group of versions? action
- Which associated ISSNs are supported by the linking record rather than inferred from matching titles? boundary
Title transitions
Track documented changes without assuming identifier continuity.
Continuity decision
Record authority-supported title relationships and unresolved changes requiring assessment.
- What predecessor, successor, merger or split relationships are documented for this assignment? provenance
- For an observed title change, has the authority confirmed continued use or a different ISSN? action
- Which historical titles and periods must remain distinguishable during retrieval or record matching? boundary
ISSN use decisions Determine whether the available evidence supports a particular identifier operation.
An ISSN can be correctly formed and assigned while still being unsuitable for a proposed match or assertion.
Matching and display
Assess use in catalogue reconciliation, citation and publication display.
Operation fit
Make the intended matching level and limits of the identifier explicit.
- Would using this ISSN merge records for the same assigned resource and medium, or conceal a version or title difference? action
- Does the proposed display clearly distinguish the ISSN from an ISSN-L? action
- Is anyone treating assignment as evidence of quality, ownership or access rights that the identifier does not establish? boundary
Correction and reverification
Route uncertain or incorrect uses toward an evidence-backed resolution.
Next authorised step
Distinguish local formatting repairs from assignment questions requiring an ISSN centre.
- Can the issue be resolved by a documented formatting correction, or does it concern the assignment itself? action
- Which responsible ISSN centre and supporting publication evidence are needed for an assignment or correction request? action
- What change or unresolved conflict requires rechecking the authority record before further use? action
What the second pass must settle
- Which current ISSN Manual rules distinguish major from minor title changes for the resource types this model must support?
- Which authoritative status terms describe cancelled, suppressed or otherwise problematic assignments, and what uses remain appropriate for each?
- How should separate online formats, language editions, supplements and integrating resources be distinguished under current assignment rules?
- Which ISSN Portal interfaces, access conditions and update mechanisms can support repeatable automated verification?
- Does an existing Vercy world model already own this identifier concept, requiring this registry entry to link to it instead of producing a separate publication?