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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so safety is covered; the description usefully adds the cost model (paid per server, see list_paid_tools) and the token-savings claim (70-90% fewer tokens) and confirms no map mutation ('Reads the map only'). It does not disclose rate limits or failure behavior, so not a 5.

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-loads the key routing instruction ('Use this instead of...') and packs the return shape, cost savings and payment note into three tight sentences with no filler. Dense but every clause earns its place.

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 fills the gap by describing what each card contains (purpose, arguments with * markers, risk level, side effects, hash). Payment and filtering are covered; only edge behavior (failure modes, token accounting) is left implicit.

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%, so parameters are already documented; per the rubric this sets a baseline of 3. The description adds only light context ('Optionally only the named tools', payment pointer) and says nothing about the last_trip reporting object beyond what the schema already describes.

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 and resource: returns one compact card per tool for a named server (what it does, arguments with required ones marked *, risk level, side effects) plus a definition hash. This is clearly distinguishable from siblings like preflight or list_paid_tools without opening either schema.

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 frames the selection condition: use it instead of loading full tool definitions when only choosing a tool or preparing a call, and points to list_paid_tools for payment. It does not state when NOT to use it (e.g. when full definitions are actually needed), so it stops short of a 5.

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