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Companies House

by io.github.pipeworx-io

Get Persons With Significant Control

get_persons_with_significant_control
Read-onlyIdempotent

Retrieve PSC (beneficial owner) records for a UK company by company_number (from search_companies). Returns each PSC's name, kind (individual-person / corporate-entity / legal-person), natures of control (e.g. ownership-of-shares-75-to-100-percent), country of residence, nationality, notification date, and ceased date.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
start_indexNoPagination offset (default 0)
company_numberYesUK company number (e.g. "07098618") OR the company NAME (e.g. "Ocado Group") — a name is resolved here automatically and the match is echoed back as resolved_from_name. Pass whichever you have; do not guess a number from memory, since a plausible wrong one returns a clean empty result that reads as "nothing filed" for a company that may not exist.
items_per_pageNo1-100 (default 25)

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
totalYesTotal number of persons with significant control
personsYesList of beneficial owners with significant control
company_numberYesUK company number
resolved_from_nameNoPresent only when a NAME was passed instead of a number. Shows which company answered, so a caller can see the resolution rather than assume it.

TDQS

A4.2/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds value by detailing what data is returned (name, kind, natures of control, etc.), which goes beyond the annotations and helps the agent anticipate the response. It does not mention pagination behavior, but that is covered by the schema parameters.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two clear sentences with no fluff. The first sentence states the core action and input; the second lists the returned fields. Each sentence earns its place and provides high-value information in a compact form.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (3 params, output schema present, strong annotations), the description is adequately complete. It explains the purpose, the input source, and the return fields. It does not elaborate on pagination or name resolution, but the schema covers those details, so the description does not need to repeat them.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already fully documents all three parameters. The description adds minimal parameter-related context: it mentions company_number comes from search_companies. It also slightly misleads by saying 'by company_number' while the schema notes the parameter can also accept a company name, but since the schema is explicit, the impact is limited.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description starts with a specific verb 'Retrieve' and clearly identifies the resource: 'PSC (beneficial owner) records for a UK company'. It also lists the key input (company_number) and differentiates from sibling tools like get_officers or get_company by focusing on PSC/beneficial owner records.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear context for when to use this tool: when you need PSC/beneficial owner records for a UK company. It also hints at a prerequisite by saying 'by company_number (from search_companies)', implying you should first use search_companies to obtain a valid company_number. However, it does not explicitly name alternative tools or state when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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TDQS

A3.6/5.0
Disambiguation2/5

Several tools have overlapping jobs: ask_pipeworx_beta is currently identical to ask_pipeworx, ask_pipeworx_grounded is the same router with stricter extraction, and discover_tools/suggest_questions both serve discovery. Company-facing tools also overlap (entity_profile vs recent_changes vs compare_entities), so an agent could easily route a query to the wrong tool despite detailed descriptions.

Naming Consistency3/5

Names are mostly snake_case and grouped prefixes like get_*, ask_pipeworx*, and polymarket_* are readable. However, conventions are mixed across the set: some are verb_noun (search_companies), some are noun phrases (entity_profile, deep_research, recent_changes), and the Companies House family sits awkwardly beside unrelated Pipeworx and prediction-market families.

Tool Count1/5

With 36 tools, the server is already heavy, but only five tools actually serve the named Companies House domain. The other 31 belong to Pipeworx querying, memory, subscriptions, and Polymarket trading, which is a severe mismatch between the server's stated purpose and its actual surface.

Completeness3/5

For UK company data, the core surface is mostly covered: search, company profile, filings, officers, and PSCs. However, charges and official document retrieval are missing even though get_company links to them, and the unrelated tools do nothing to complete the Companies House domain.

Resources