Claims Drafting: The Core Patent Skill

Claims Drafting: The Core Patent Skill

Draft patent claims based on: $ARGUMENTS

This is the most critical skill in the patent pipeline. Claims define the legal scope of protection -- everything else (specification, figures, abstract) exists to support and enable the claims.

Constants

• REVIEWER_MODEL = gpt-5.5 — External examiner for claim quality review
• MAX_CLAIM_REVISION_ROUNDS = 3 — Maximum revision iterations
• CLAIM_STYLE = "auto" — US (Jepson or open), EP (two-part mandatory), CN (two-part), auto (detect from jurisdiction)
• MIN_INDEPENDENT_CLAIMS = 2 — Typically method + system. For utility model (实用新型): apparatus/device only, NO method claims.
• MAX_TOTAL_CLAIMS = 20 — Practical limit (USPTO includes 20 in base fee)
• PATENT_TYPE = "invention" — invention (发明专利) or utility_model (实用新型, apparatus claims only)

Inputs

1. patent/INVENTION_DISCLOSURE.md — structured invention with core/supporting/optional features
2. patent/PRIOR_ART_REPORT.md — prior art to avoid
3. patent/NOVELTY_ASSESSMENT.md — novelty analysis with suggested amendments
4. Target jurisdiction from invention disclosure or $ARGUMENTS

Shared References

Load ../shared-references/patent-writing-principles.md for claim drafting principles, antecedent basis rules, and common pitfalls. Load ../shared-references/patent-format-cn.md for CN claim format (其特征在于). Load ../shared-references/patent-format-us.md for US claim format (comprising, means-plus-function). Load ../shared-references/patent-format-ep.md for EP two-part form (characterised in that).

Workflow

Step 1: Determine Claim Style and Patent Type

Based on patent type and jurisdiction:

If PATENT_TYPE = utility_model (实用新型):

• CN jurisdiction ONLY
• Apparatus/device claims ONLY — no method, no product-by-process
• MIN_INDEPENDENT_CLAIMS = 1 (single apparatus claim is sufficient)
• Claim format: "1. 一种[主题]，其特征在于，包括：[组件描述]。"

Based on target jurisdiction:

Jurisdiction	Claim Style	Characterising Phrase	Preamble Format
CN	Two-part (两部式)	其特征在于	一种...的方法/装置，包括：
US	Open (preferred)	comprising	A method for..., comprising:
EP	Two-part (mandatory)	characterised in that	A method for..., comprising [known], characterised in that [inventive]
ALL	Draft CN + US + EP	All of the above	All of the above

Step 2: Draft Independent Claims

CRITICAL — Claims numbering (CN format):

• Claims must be numbered 1, 2, 3, ... continuously without gaps
• Independent and dependent claims are INTERMIXED in final numbering
• Do NOT group independent claims separately from dependent claims
• Example correct: Claim 1 (independent, product), Claim 2 (depends on 1), Claim 3 (depends on 1), Claim 4 (independent, method), Claim 5 (depends on 4)...
• Example WRONG: Claim 1 (independent), Claim 5 (independent), Claim 8 (independent), then Claim 2, 3, 4, 6, 7, 9, 10 as dependents

CRITICAL — No empirical content in claims:

• Claims describe ONLY structural features or method steps
• Do NOT include signal characteristics, detection principles, measurement results
• WRONG: "产生负脉冲信号" / "谐振频率下降" — these are results, not features
• RIGHT: "所述开口谐振环的开口处形成用于检测通过流体中颗粒物的间隙传感区域"

For each claim category identified in INVENTION_DISCLOSURE.md:

Method Claim (broadest):

1. Start with preamble identifying the category and purpose
2. List the core inventive features (from the "Core Inventive Concept" section)
3. Include enough known features for context (but not more than necessary)
4. Use open transition ("comprising" / "包括")
5. Each element should be separated by semicolons or on separate lines
6. Apply jurisdiction-specific format:
   • CN: 前序部分 + "其特征在于" + 特征部分
   • US: Preamble + "comprising:" + elements
   • EP: Preamble + known features + "characterised in that" + inventive features

System/Apparatus Claim:

1. Mirror the method claim in structural form
2. Each method step becomes a "module configured to..." or "component for..."
3. Same hierarchy of known vs. inventive features

Quality checks for each independent claim:

• [ ] Single sentence (US/EP) or properly structured (CN)
• [ ] Antecedent basis: "a" first, "the" thereafter for each element
• [ ] No relative terms without definition
• [ ] No result-to-be-achieved limitations
• [ ] Transitional phrase is appropriate (open preferred)
• [ ] Preamble does not import unnecessary limitations
• [ ] Each element is necessary for patentability
• [ ] Claim scope is broadest defensible over prior art

Step 3: Draft Dependent Claims

For each independent claim, draft 5-10 dependent claims that:

1. Narrow the core inventive features: Specific implementations, parameters, ranges
2. Cover preferred embodiments: Features from the specification's detailed description
3. Provide fallback positions: If the independent claim is rejected, these narrower claims may survive
4. Cover alternatives: Different ways to achieve the same inventive result

Dependent claim format:

• CN: "根据权利要求X所述的[主题]，其特征在于，所述[特征]具体为..."
• US: "The [method/system] of claim X, wherein the [element] comprises [limitation]."
• EP: "The [method/system] according to claim X, characterised in that [limitation]."

Rules for dependent claims:

• Each must add at least one meaningful limitation
• Must reference a prior claim by number
• Must not merely repeat the parent claim
• Should not be cumulative (each claim should be independently useful as a fallback)
• Multiple dependent claims (US: only "or" references, not "and")

Step 4: Claim-to-Specification Mapping

Create a preliminary mapping to verify enablement:

Claim Element	Must be described in specification	Reference numeral
[element 1]	Yes/No	[numeral]
[element 2]	Yes/No	[numeral]

If any element lacks specification support, add it to the specification requirements.

Step 5: Cross-Model Examiner Review

Start the examiner review with a dedicated Codex reviewer agent at xhigh reasoning:

spawn_agent:
  model: gpt-5.5
  reasoning_effort: xhigh
  message: |
    You are a senior patent examiner at the [USPTO/CNIPA/EPO].
    Review the following patent claims for quality and patentability.

    CLAIMS: [all claims]

    PRIOR ART: [prior art references from PRIOR_ART_REPORT.md]

    INVENTION: [summary from INVENTION_DISCLOSURE.md]

    Analyze each claim for:
    1. Clarity (35 USC 112(b) / Art 84 EPC): Are terms definite?
    2. Written description support: Does the spec support all claim scope?
    3. Anticipation (102/Art 54): Would any single reference anticipate?
    4. Obviousness (103/Art 56): Would any combination render obvious?
    5. Claim scope: Are independent claims broad enough to be valuable?
    6. Dependent claims: Do they provide meaningful fallback positions?
    7. Antecedent basis: Any issues with "a"/"the" usage?
    8. Indefinite terms: Any functional/result language issues?

    For each issue found, provide:
    - The specific claim number and element
    - The problem (cite statute/rule)
    - A suggested fix

    Provide an overall PATENTABILITY SCORE: 1-10.

Step 6: Revision Loop

If the examiner review identifies issues:

1. Address all CRITICAL issues (anticipation, obviousness, indefiniteness)
2. Address MAJOR issues (scope too narrow, missing support, weak fallbacks)
3. Consider MINOR issues (antecedent basis, formatting)
4. Re-submit to the same examiner via send_input using the saved reviewer id
5. Repeat up to MAX_CLAIM_REVISION_ROUNDS times

send_input:
  target: [saved reviewer id from Step 5]
  message: |
    Here is the revised claim set after addressing the previous office action.

    Revised claims:
    [full revised claims]

    Focus only on unresolved or newly introduced issues.

Step 7: Output

Write patent/CLAIMS.md:

## Patent Claims

### Independent Claims

#### Claim 1 — Method
[formatted claim text]

#### Claim X — System/Apparatus
[formatted claim text]

### Dependent Claims

#### Claim 2 (depends on 1)
[formatted claim text]

#### Claim 3 (depends on 1)
[formatted claim text]
...

### Claims Summary Table

| Claim | Type | Depends On | Key Limitation | Prior Art Avoidance |
|-------|------|-----------|----------------|---------------------|
| 1 | Method | — | [core inventive features] | [what makes it novel over prior art] |
| 2 | Method | 1 | [narrowing] | [additional distinguishing] |
| X | System | — | [mirrors claim 1] | [same as claim 1] |
...

### Examiner Review Summary
[Key findings and how they were addressed]

Key Rules

• Claims are the single most important part of the patent. Everything else supports them.
• Draft independent claims first, then dependent claims.
• Independent claims must be broadest defensible scope over prior art -- not broader, not narrower.
• Each dependent claim should be independently useful as a fallback position.
• Antecedent basis is mandatory: "a processor" first, "the processor" thereafter.
• Use "comprising" (open) unless there is a specific reason for "consisting of" (closed).
• Never include result-to-be-achieved language in claims ("configured to achieve high accuracy").
• Never fabricate claim language -- every element must come from the actual invention.
• If drafting for ALL jurisdictions, produce separate claim sets for CN, US, and EP.
• If reviewer delegation is unavailable in the current Codex host, stop and ask the user to enable Codex agent support before continuing the examiner loop.