Draft the way the EPC evaluates: map every disclosure feature as essential, embodiment detail or alternative; put the effect-bearing feature in the characterising portion of a two-part independent claim; build a dependent-claim ladder as fallback; and run novelty, inventive-step and Article 123(2) added-matter self-checks before finalising anything.
Turning an invention disclosure into a compliant application
A Paper A-style task asks you to convert a technical disclosure into claims and a description satisfying the EPC: claim category, essential features, support, and fallback positions, all decided before writing begins.
Read the disclosure twice. First pass: identify the technical problem, the solution, and the effect the disclosure attributes to that solution — usually one feature or a tight combination. Second pass: inventory every technical feature and label it 'essential to the effect', 'embodiment detail', or 'alternative'. That three-way label decides claim placement for the rest of the task, so write the labels down rather than holding them in your head.
Drafting is legal decision-making under the EPC because every claim word is a limitation assessed for clarity (Article 84), and the claim must be supported and enabled through the description (Articles 83–84). The same disclosure can yield a broad claim an examiner attacks, or a narrow claim that survives but protects little. Your job is to choose the breadth the disclosure actually justifies, and to make that justification visible in the description.
Two-part form and the feature hierarchy: build the skeleton first
Rule 43(1) EPC favours two-part form: a preamble reciting features shared with the closest prior art, a characterising portion with the distinguishing features, linked by 'characterised in that'. The hierarchy comes next.
Two-part form splits the claim into a preamble reciting features shared with the closest prior art and a characterising portion reciting what is new. Choosing the characterising portion forces your first real decision: which feature carries the stated technical effect. Name that effect in the description, because it becomes the backbone of the inventive-step argument and of every fallback claim beneath the main claim.
Build the hierarchy after the main claim. Each dependent claim adds exactly one or two features in decreasing order of how much protection you expect to need, and each must include every limitation of the claim it depends on. Alternatives ('A or B') belong only where the disclosure supports the generalisation; scattering 'or' through the main claim is how unsupported breadth and clarity objections arrive together.
Scenario 1: when the preferred embodiment hijacks the main claim
The trap is copying the preferred embodiment wholesale into the independent claim. The better move: claim the feature that produces the effect, and push embodiment details into dependent claims.
Scenario: a disclosure describes a valve in which a chamfered groove edge keeps a sealing ring seated under pressure pulses. The preferred embodiment also specifies a named fluorinated elastomer and exact thread dimensions. A tempting first draft recites all of it, because it matches the drawing. The mistake: the elastomer and thread pitch say nothing about the stated effect, so the claim becomes narrow without becoming safer.
The better claim puts the chamfered groove edge — a structural feature — in the characterising portion, keeps 'an elastic sealing element' generic, and moves the elastomer and threads into dependent claims. Why it matters: if a prior-art document shows the same elastomer in a plain groove, the narrow claim reads on it and falls on novelty; the chamfer claim still distinguishes, and inventive step can be argued from the pressure-pulse effect the disclosure describes.
Novelty and inventive-step self-checks while the claim can still change
Before finalising, run a novelty attack on your own claim using the prior art in the paper, then an inventive-step argument keyed to the technical effect. Adjust breadth during drafting, not after.
Run the novelty check claim-first: for each prior-art document in the paper, map every claim feature to a passage. One unmapped feature means novelty holds, and that feature is your distinguishing feature. Then test it against the description: if the disclosure attributes no effect to it, you have a formally novel claim with no inventive-step story — a signal to pull a different feature forward while drafting is still open.
Frame inventive step the way the problem–solution approach in the EPO's Guidelines for Examination structures it: the objective technical problem combines the distinguishing feature with the effect the disclosure attributes to it, seen from the closest prior art. If the effect merely achieves the same result another way, an obviousness argument is available against you, so prepare the fallback: the next dependent claim adds a feature tied to a stronger effect.
Scenario 2: the amendment that quietly adds matter
Amendments must stay within the original application (Article 123(2) EPC). The trap is combining a dependent-claim feature with a feature from a separate embodiment that were never disclosed together.
Scenario: you amend the valve claim set by adding 'the sealing ring is a perfluoroelastomer' (from dependent claim 3) and 'the groove is formed in two mating halves' — a feature disclosed only in a separate embodiment. Neither the original claims nor any single passage discloses that combination. Under Article 123(2) EPC an amendment must not go beyond the content of the original application, and this one does.
The better move: incorporate dependent claim 3 in its entirety, which is directly and unambiguously derivable from the original claims, or if the two-half feature is genuinely needed, cite the original passage supporting each feature and confirm a disclosed combination exists before drafting it. Why it matters: an added-matter objection cannot be argued away; it can only be answered by reverting, which costs the very fallback position the amendment was meant to reach.
Unity, priority and claim category: decisions that shape the whole application
One invention per application (Article 82 EPC): claims sharing a common inventive concept stay together. Claim category (product, process, use) and priority coverage should be settled when structuring claims, not retrofitted.
Claim category is a scope decision. If the commercial value sits in the product, a product claim covers it however made; a process claim reaches only the process, and a use claim only the use. Priority works the same way early: where the paper gives an earlier filing, check which features it actually disclosed — features added later take a later effective date, which matters if intervening prior art appears between the two dates.
Article 82 EPC requires the claims to relate to one invention, understood through a common inventive concept. A broad genus claim plus species claims stays unified while the genus carries the inventive concept; once the genus is merely a collection of species with a shared label, unity questions follow. Keep the shared technical effect visible in the main claim and the description so the whole set hangs together.
Use this placement table while structuring any claim set:
| Feature situation | Better placement | Reasoning |
|---|---|---|
| Produces the stated technical effect and is absent from the closest prior art | Independent claim, characterising portion | Carries novelty and inventive step for the entire set |
| Present in the closest prior art | Preamble | Two-part form records what you accept as known |
| Shown in only one embodiment | Dependent claim or described embodiment | Keeps the main claim broad while preserving support (Article 83) |
| Optional alternative | Dependent claim, or 'A or B' only where the disclosure supports it | Avoids unsupported generalisation |
| Explanation of the technical effect | Description | Feeds the inventive-step argument; not a claim limitation by itself |
A rehearsal exercise, a self-check rubric and a preparation sequence
Rehearse the full pipeline on short disclosures: feature map, two-part main claim, fallback ladder, amendment drill. Score each attempt against a fixed rubric so progress stays measurable.
Exercise: take any one-page self-written disclosure containing one effect-bearing feature and two embodiment variations. Work 60 minutes: 15 for the feature map, 20 for the two-part main claim, 10 for three dependent claims, 15 for rubric review. Expected observations to check: whether the effect-bearing feature actually reached the characterising portion, whether a single-embodiment detail crept into the main claim, and whether each dependent claim narrows in one defined, useful way.
A workable sequence: spend the first stretch on the EPC provisions that govern this drafting — Articles 52–57, 82–84 and 123, plus Rule 43 — reading them alongside the Guidelines for Examination. Then run untimed drills, timed full exercises, and an amendment drill where a prior-art document is revealed after you have drafted and you must restructure the claim set. Check the EPO website for the administrative details of the 2026 final session; logistics sit outside this guide.
- Rubric: every feature in the characterising portion traces to explicit support in the disclosure.
- Rubric: the preamble contains no feature the paper presents as new.
- Rubric: the fallback ladder holds at least two dependent claims of distinct breadth, each narrower in one defined way.
- Rubric: no purely result-defined limitation appears where a structural alternative exists.
- Rubric: in the amendment drill, you can cite the original passage for every added feature.
- Readiness check: you can state and answer a novelty attack on your own claim in two sentences.
- Readiness check: you can explain, citing the standard, why a proposed amendment does or does not add matter.
- Readiness check: you use the feature-placement table unprompted when structuring a claim set.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.