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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, but the description adds real context beyond them: results are computed deterministically by code rather than generated, and the response shape is 'calculator id + input keys + defaults'. The only muddiness is the final sentence telling the caller to answer with returned numbers, which does not obviously fit a listing operation.

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 long domain enumeration is front-loaded and arguably earns its length by helping an agent judge coverage, but it is a dense undifferentiated list that could be grouped. The trailing sentence about answering with returned numbers adds no value for a catalog tool and slightly muddies the purpose.

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 output schema, the description correctly compensates by describing the return payload (ids with input keys and defaults). For a one-optional-parameter read-only listing tool that is close to sufficient; the missing piece is any hint about how the optional filter is applied.

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?

There is a single optional parameter with 100% schema description coverage that already explains the filter with examples ('cable', 'finance'). The description says nothing about the query filter or how filtering matches (by name, domain, keyword), so it adds no meaning beyond the schema — baseline 3 applies.

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 description names a specific verb and resource (a catalog of deterministic calculators) and enumerates the covered domains, so an agent knows it is a discovery tool rather than the calculation tool. It never names the sibling it is paired with (presumably wai_calculate), so the boundary is implied rather than stated.

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 mention of returning 'each calculator id with its input keys and defaults' signals this is the lookup step before calling a calculator, but there is no explicit 'use this before wai_calculate' or 'do not use this to compute'. The closing instruction about answering with returned numbers reads like shared boilerplate and does not clarify when to select this tool.

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