UK Parliament MCP Server

get_annulment_date

Calculate the annulment date for a negative statutory instrument or treaty using its laid date and scrutiny period, returning when it will be annulled.

Instructions

Get annulment date | SI annulment, negative SI, scrutiny period, 40 days | Calculate the annulment date for a negative statutory instrument | Returns annulment date

    Args:
        date_laid: Date the negative SI was laid (YYYY-MM-DD).
        days_in_future: Number of days from date_laid when the SI will be annulled (e.g. 40).
        is_treaty: Whether the SI is a treaty or agreement (default: false).

    Returns:
        Calculated annulment date for the statutory instrument.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`date_laid`	Yes
`is_treaty`	No
`days_in_future`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 6, 2026

TDQS

A3.5/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full burden. It is a pure calculation, so the main behavioral question is whether the day count includes sitting days, recesses, or is calendar-only, and whether the calculation accounts for treaty-specific rules. The description hints at treaty handling via is_treaty but does not disclose the calculation basis, leaving a meaningful gap for a date-sensitive tool.

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

Conciseness3/5

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

The opening line duplicates the same information three times ('Get annulment date | ... | Calculate the annulment date ... | Returns annulment date'), and the Returns line restates what the Args section already implies. The Args block itself is well-structured, but the redundant front matter and pipe keyword stuffing waste space.

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?

With an output schema present, return-value detail is unnecessary, and the description adequately documents all three parameters for a low-risk calculation. The main missing piece is the behavioral basis of the calculation (calendar days vs sitting days, treaty handling), which matters for trusting the result.

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

Parameters4/5

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

Schema description coverage is 0%, so the description must compensate, and it does: it defines date_laid as the laying date with a YYYY-MM-DD format, days_in_future as the number of days from date_laid with an example (40), and is_treaty as whether the SI is a treaty/agreement with a default of false. This is solid compensation for the empty schema.

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

Purpose4/5

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

The description states a specific verb and resource: 'Calculate the annulment date for a negative statutory instrument', which is distinct from sibling SI tools like get_si_procedures or get_si_timeline_business_items. The pipe-separated keyword prefix ('SI annulment, negative SI, scrutiny period, 40 days') is noisy but reinforces the domain. It does not explicitly contrast itself with any sibling, so it stops short of a 5.

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

Usage Guidelines3/5

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

Usage is only implied through the domain context ('negative SI', 'scrutiny period', '40 days'), which tells an agent this is for the negative-SI annulment calculation. There is no explicit statement of when to use this versus related SI timeline tools, and no exclusions or prerequisites are given.

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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