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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds genuinely useful interpretation caveats absent from structured fields: the total is not per-series availability, and source/schema checks are not independent verification. That is real added context, not restatement.

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?

Capabilities come first, then invocation mode, then routing alternatives, then two caveats — a sensible front-loaded order. Sentences are dense but each carries either routing or a caveat, with minimal filler; slightly packed to read as a 5.

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 an output schema present, the description needn't detail return values, and it stays focused on capabilities, usage, and interpretation limits. It is essentially complete for a zero-parameter introspection tool, missing only minor specifics about what the overview contains.

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 are zero parameters, which puts the baseline at 4. The description reinforces this by stating it should be called with no arguments, so the agent knows no inputs are expected. Nothing further is needed.

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 gives a concrete verb ('Inspect') and enumerates the resources surfaced: service capabilities, HTTP endpoints, refresh policies, pricing, and validated-record totals. It also explicitly distinguishes itself from list_topics and list_sources, so an agent can tell it apart from siblings. The scope is a slight grab-bag, which keeps it short of a 5.

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?

It states the invocation mode ('Call with no arguments for a service overview or integration setup') and routes to named alternatives with their selecting conditions ('prefer list_topics', 'use list_sources'). This is explicit when-to-use and when-to-use-something-else guidance.

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