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

Annotations already declare read-only, idempotent, closed-world behaviour, so the bar is lower; the description still adds real value by disclosing the houses-or-units fallback when a block has no house figure and by clarifying that only values are returned, not geometry. It stops short of noting coverage or how many blocks come back.

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?

Two short sentences, front-loaded with the horizons and granularity, with the geometry pointer trailing as a useful aside. The awkward line break and backtick path reference are the only rough edges; nothing is redundant.

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?

For a one-parameter read tool with no output schema, the description covers units (percent, cumulative), fallback logic and the division of labour with the shapes tool. A brief note on return shape or the identifier format would have closed the remaining gap.

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 0%, so the description carries the burden, and it only implies the single parameter through 'in the suburb'. It does not state whether suburb_name is a display name, slug or ID, or how ambiguous names resolve.

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 (past price growth at 1/3/5/10-year horizons) and a specific granularity (every mesh block in the suburb), with units (percent, cumulative). It implicitly differentiates from suburb-level growth siblings but never names them, so an agent must still guess between this and suburbs_market_price_growth without reading both schemas.

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 'by mesh block' framing and the note that polygons come from /shapes/mesh-blocks hints at when to pair it with a shape source. There is no explicit when-to-use, no exclusion of the many suburb-level growth siblings, and no statement that this requires a mesh-block-level analysis.

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