compare_loyalty_points_valueEvery UK loyalty scheme CardPoints covers, ranked by what its usual earning rate gives back per £1: points per £1, what one point is worth, and the date each scheme's figures were read from its own terms.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description still adds value by disclosing coverage ('every UK loyalty scheme CardPoints covers') and, importantly, that each scheme's figures carry the date they were read from that scheme's own terms – a freshness/provenance caveat an agent would not get from annotations.
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?
A single front-loaded sentence that names the resource, the ordering, and the three returned fields with zero filler. Nothing could be cut without losing information.
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?
With no input parameters and no output schema, the description carries the return-value burden and does so by enumerating the fields returned. It could be slightly stronger by stating that results are sorted/complete and roughly how large the index is, but for a zero-arg read tool it is essentially sufficient.
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 tool takes no parameters, so the baseline is 4. The description correctly frames the call as a parameterless full-index retrieval and adds no misleading argument expectations.
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?
States a specific resource and scope: a ranked index of every UK loyalty scheme CardPoints covers, with the three metrics it reports (points per £1, value per point, figures-read date). This implicitly distinguishes it from single-scheme siblings like get_loyalty_scheme, but it never names an alternative explicitly.
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?
Usage is only implied: the cross-scheme ranking framing suggests 'use this to compare schemes', while find_points_at_shop and get_loyalty_scheme handle narrower lookups. There is no explicit when-to-use, when-not-to-use, or named alternative.
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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