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

With no annotations provided, the description carries the full behavioral burden. It discloses the official daily public extract source, explicitly states that contact addresses, phone, email, and trustee names are never ingested, and notes the credit cost per call. It does not discuss pagination or rate limits, but the key constraints are covered.

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

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

The description is dense and information-rich, covering source, scope, fields, exclusions, filter behavior, and cost in just two sentences. The field enumeration is slightly run-on, but every clause earns its place and no filler is present.

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

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

Given 23 parameters and no output schema, the description provides a solid overview of scope, returned fields, and exclusions, but lacks per-filter value guidance, pagination details, and response shape. It is minimally viable but not fully complete for invoking all filters correctly.

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

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

The schema has 0% description coverage across 23 parameters, and the description only explains q ('searches all text fields') and the AND-combination behavior. It leaves expected values for string filters (is_cio, gift_aid, insolvent), date semantics, and pagination parameters undocumented, relying too heavily on parameter names.

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

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

The description names the exact dataset ('Charity Commission register for England and Wales') and enumerates the returned fields, making it easy to distinguish from sibling query_uk_* tools. It also clarifies that 'q searches all text fields' and that filters combine with AND, reinforcing the retrieval purpose.

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

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

No explicit when-to-use or when-not-to-use guidance is given, and no alternative tools are named. The description provides clear context—UK charity data from the Charity Commission—but leaves the choice among siblings mostly implicit.

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