UK legal research using the Lex API. Use this skill whenever the user asks about UK law, legislation, statutory instruments, Acts of Parliament, legal provisions, amendments, or anything that could benefit from searching authoritative UK legal sources. Also use when the user mentions specific UK Acts (e.g. "the Data Protection Act"), asks about legal requirements, or needs to understand how legislation has changed over time. Even if the user doesn't explicitly say "search legislation", if they're asking a question that UK law could answer, use this skill.
You have access to the complete corpus of UK legislation from The National Archives via MCP tools. This skill teaches you how to conduct thorough legal research — not just which tools exist, but how to use them together effectively.
Different questions need different approaches. Choose the right workflow for the task.
When the user asks about a legal topic (e.g. "unfair dismissal", "data protection for AI"):
search_for_legislation_acts with a natural language query. Set include_text: false for speed — you only need titles and IDs at this stage.search_for_legislation_sections for each relevant Act found. Pass the legislation_id to scope your search. This is where the substantive law lives. Use include_text: true when you need to verify a result is genuinely relevant — title matches can be misleading for generic section titles like "Interpretation" or "Extent".search_amendmentsget_explanatory_note_by_legislation or get_explanatory_note_by_section to understand Parliament's intent. Not all Acts have explanatory notes — they're generally available for post-1999 legislation, but even some recent Acts lack them.The goal is to present a complete picture: what the law says, how it has changed, and what Parliament intended.
When the user asks about a specific provision:
lookup_legislation with legislation_type, year, and number.search_for_legislation_sections with the legislation_id and an empty query to retrieve by filter.search_amendment_sections with the provision_id (e.g. "ukpga/1998/42/section/3"), then also search_amendments at the Act level. Section-level search finds textual amendments; Act-level search catches disapplications by later Acts. Both are needed for a complete picture.get_explanatory_note_by_section for context on what the provision means.When the user asks about changes to legislation:
search_amendment_sections with the provision_id (e.g. "ukpga/1998/42/section/3"). The provision_id must include the section path, not just the Act ID.search_amendments with the legislation_id. This catches amendments that section-level search may miss — particularly disapplications, where a later Act limits where the provision applies without changing its text. Disapplications are enacted by other Acts and may not appear in section-level amendment results.search_for_legislation_sections with a query like "amends [Act name]" or "section [N] [Act name]". Other Acts may reference or modify the provision's effect without being recorded as formal amendments. This fallback is particularly important for pre-2001 legislation, where structured amendment data is sparse.get_explanatory_note_by_legislation for an overview of the whole Act, or get_explanatory_note_by_section for a specific provision.search_explanatory_note with a natural language query if you don't know which Act is relevant.note_type to focus on specific sections of the explanatory material (overview, policy_background, legal_background, extent, provisions, commencement, related_documents).The database contains ~85,000 Acts from 1267 onwards, including major public general Acts. When researching historical legislation:
year_from and year_to work reliably across the full date range. Use them to narrow results to the relevant period.search_for_legislation_sections using the legislation_id and include_text: true to read the actual provisions.ukpga/Vict/8-9/20 for 8 & 9 Vict. c. 20). These work as legislation_id values in all tools.search_for_legislation_acts returns whole Acts ranked by relevance. If the user wants specific provisions, use search_for_legislation_sections instead — or use Acts search first, then sections search to drill in.search_amendment_sections finds direct textual amendments but can miss disapplications enacted by other Acts. Always also run search_amendments at the Act level — this is how you find provisions like the Victims and Prisoners Act 2024 disapplying HRA s.3 in specific contexts.include_text: true and read the actual provision before citing it — especially for sections with generic titles.search_for_legislation_acts — find Acts/SIs by topic. Key params: query, legislation_type, year_from/year_to, include_text, limit.search_for_legislation_sections — find provisions within legislation. Key params: query, legislation_id, legislation_type, legislation_category, year_from/year_to, size, include_text.lookup_legislation — get a specific Act by type/year/number.get_legislation_sections — list all sections of an Act by legislation_id.get_legislation_full_text — complete text. Set include_schedules: true only if specifically needed.proxy_legislation_data — enriched metadata from legislation.gov.uk.search_explanatory_note — search note content. Key params: query, legislation_id, note_type, section_type.get_explanatory_note_by_legislation — all notes for an Act.get_explanatory_note_by_section — note for a specific section number.search_amendments — Act-level amendments. Key params: legislation_id, search_amended.search_amendment_sections — section-level amendments. Key params: provision_id, search_amended.When presenting legal research: