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

Annotations already establish this as a safe, open-world read, so the bar is lower, yet the description adds genuinely useful scope limits: no regulatory approval or endorsement is implied, and no claim evidence or contact records are returned. That negative-scope disclosure prevents an agent from assuming the profile contains compliance or contact data, though it says nothing about coverage or lookup-miss behaviour.

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?

Three sentences, front-loaded with the core action, with scope disclaimers and access terms following in decreasing importance. The endorsement disclaimer is mildly legalistic but earns its place as a scope boundary; nothing is redundant with the annotations.

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?

This is a simple single-parameter read tool with a full output schema, so return shape need not be described. The description covers what is returned, what is excluded, and access requirements; only the failure mode for an invalid or missing slug is unaddressed, which is a minor gap given the low complexity.

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 single parameter is fully documented in the schema (100% coverage) including its exact format — 'lowercase hyphenated organisation slug from a directory search result'. The description adds 'by slug' but no new meaning beyond the schema, so the baseline of 3 applies.

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 opening clause gives a specific verb and resource — 'Read one sourced public organisation summary by slug' — and enumerates the payload (services, original sources, canonical FXMacroData citation URL). It implicitly separates itself from the directory listing tool via 'from a directory search result' in the schema, but never names organisation_search, so the sibling distinction is inferred rather than stated.

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?

The description implies the precondition that a slug must already exist (you cannot read a profile without one) and adds access context ('no API key required', 'one public organisation summary'). However, it never explicitly says to call organisation_search first or when to prefer that tool, leaving routing guidance to inference.

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