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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so safety is covered; the description goes well past that by disclosing ambiguity handling (up to 3 candidates), mismatch warnings for block/street/floor, the 'unknown' fallback for building type, data provenance (OneMap/SLA, LTA, HDB via data.gov.sg), and latency-relevant detail about what the normalized result contains. These are behavioral traits an agent could not infer from the schema.

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?

It is front-loaded with the 'Use when' trigger and then the return contract, and there is no filler. The main weakness is that the opening sentence is a long enumerated run-on listing many question types, which could have been a compact bulleted list for faster scanning.

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 and only one parameter, so the description must carry the return contract itself, and it does: normalized block/street/postal/unit, coordinates, district, HDB town, two nearest MRT/LRT stations with distance and walking time, building type, and delivery note. Combined with the ambiguity and mismatch caveats, an agent has everything needed to call it and interpret the result.

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% and the single 'query' parameter is already well documented in the schema, so the schema carries most of the burden. The description adds a concrete worked example, {"query":"570151"}, which anchors the expected format and implicitly confirms that a bare postal code is acceptable input.

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 title and first sentence state a specific verb and resource: resolve a Singapore address, postal code, unit number, or building name into a normalized address with enrichment. It also enumerates the exact facts it can answer (building type, HDB/condo/commercial classification, MRT proximity, district, delivery notes), so an agent can distinguish it from every sibling, which are all quote/order/weather utilities with no overlap.

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 opens with an explicit, trigger-style 'Use when the user gives or asks about...' clause and then lists concrete question shapes (what postal code is this, is it an HDB block, how far is the MRT, what a courier needs), so an agent knows exactly which user utterances should route here. It also states a hard scope exclusion, 'Singapore only', which prevents misuse for other geographies.

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