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

Annotations cover the safety profile (readOnlyHint false, destructiveHint false, openWorldHint true, idempotentHint false), and the description adds genuinely non-obvious behavior: the credit is charged only on a successful fresh fetch, while cache hits and failures cost zero. It also warns that public-page engines can be blocked or incomplete, which sets expectations for partial or missing results. It stops short of saying how a block or failure is surfaced to the caller, for example as an error or as partial data.

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?

Three compact sentences open with the most important information: what is returned, then the cost model, then the reliability caveat. Each sentence carries distinct information with no filler, although the mode-economics sentence duplicates guidance already present in the schema.

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 responsibly notes that the return includes cache/cost metadata alongside the profile, and it covers cost and reliability for a network-backed tool with a charged mode. It leaves the profile payload shape loosely defined as 'normalized' and says nothing about rate limits or per-call concurrency, which keeps it from being fully complete.

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 all four parameters, including the mode and freshness enums, are already documented in the schema with defaults. The description restates the demo-is-free and live-costs model but adds no syntax or behavioral detail beyond what the schema fields already say. That lands at the baseline for fully documented parameters.

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 opens with a specific verb and resource: return a normalized public profile plus cache/cost metadata, which tells an agent exactly what it gets back. It never names a sibling, though, so an agent must infer on its own that signalshelf_batch is the multi-profile variant and signalshelf_resource is a different resource type.

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 gives clear guidance for the key decision of demo versus live, calling demo illustrative and free and noting that live charges a credit only on a successful fresh fetch. It offers no explicit exclusions or routing advice toward sibling tools, so the guidance is strong on mode choice but silent on tool choice.

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