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

Annotations already establish this is a non-destructive read (readOnlyHint=true, destructiveHint=false, openWorldHint=false), and the description adds substantial behavior beyond them: retired postcodes still resolve to their former neighbourhood, ambiguous names return candidates with ids, and unresolvable input returns a reason. Those are outcome-shaping behaviors an agent cannot infer from the 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?

Front-loaded with the verb, resource and accepted inputs, then the return shape, then usage routing — a logical order. The middle clause listing every returned field is dense but each item is informative; the description is slightly long, which keeps it from a 5.

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?

There is no output schema, so the description carries the full burden of describing returns, and it does: place id (oga_pl_...), type, name, country, nation, resolution method, postcode liveness with retirement month, candidate lists, and failure reasons. Nothing needed to call it correctly or interpret the result is missing.

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?

Schema coverage is 100% with a single required param, so the baseline is 3; the description earns an extra point by tying each accepted input form to its downstream result (postcode liveness/retirement month, candidate lists for ambiguous names, reason for non-matches). It does not add format or validation detail beyond the schema, so it falls short of a 5.

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 verb (resolve) and resource (a place), and enumerates exactly which input forms it accepts: postcode, place name, official neighbourhood code, or OneGoodArea place id, scoped to England, Wales and Scotland. This is clearly distinguishable from siblings like find_areas or score_postcode, which operate on already-known areas.

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?

Explicitly instructs to 'call it first when an input may be retired or ambiguous, or to obtain an id that survives boundary changes before calling the other tools.' It gives both the triggering condition and the ordering relationship to the sibling toolset, which is exactly the routing guidance an agent needs.

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