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

Annotations already cover the read-only/idempotent/non-destructive profile, but the description adds real behavioral context beyond them: the estimate is a 50th-percentile scaled/aged figure, FMR remains a 40th-percentile voucher number, ACS B25031 is a secondary anchor, and crucially a ZIP absent from both sources returns an error with no invented national fallback. That error/fallback contract is genuinely useful disclosure the annotations cannot provide.

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?

The description is dense and poorly front-loaded, opening with a URL reference and internal artifact names (hud-50th-sample.json, BLS CPI Shelter, ACS B25031) that read like implementation notes rather than selection guidance. Several clauses describe pipeline mechanics the agent cannot act on, diluting the signal-carrying content.

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 3-parameter estimation tool with no output schema, the description should clarify parameter meanings and what the returned estimate represents. Instead it documents data provenance and the missing-ZIP error while leaving bedrooms, the zip key, and the output value undefined. Coverage of what an agent needs to invoke it correctly is incomplete.

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 description coverage is 0% across all 3 parameters, so the description carries the full burden and largely fails it. It hints that a property-type multiplier exists (partially explaining property_type) but says nothing about the zip input or the bedrooms parameter, including its default of 2 or range 0-8. Two of three parameters remain unexplained.

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 sentence ('The rent estimator on /tools/rent-estimator') is essentially tautological and leads with a URL rather than the operation. Only deeper in the text does it become clear the tool returns a scaled/aged median rent estimate for a ZIP, and it distinguishes FMR (40th-percentile voucher figure) from the estimate. An agent can infer the purpose but must read past jargon to get there.

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?

There is no guidance on when to use this tool versus siblings like lookup_hud_rent, lookup_rent_to_income, or lookup_covered_market. The only routing signal is the missing-ZIP error case, which is a failure mode, not a usage condition. No explicit when/when-not or alternative selection is offered.

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