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

With no annotations, the description carries full responsibility for behavior disclosure. It declares the read-only nature by saying 'Retrieve an overview', specifies a representative result set (current technologies with confidence, DNS records, timestamps, observation count, latest state hash), and calls out the special 'not_observed (404-equivalent)' case when no history exists. This is meaningful behavioral information.

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 two sentences: the first states the purpose and contents, the second adds the canonical use case and the error condition. No filler words; it is front-loaded with the substantive 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?

The tool has a single parameter, no output schema, and no annotations, so the description needed to explain both input and expected output. It enumerates the main fields returned and the not_observed behavior, which gives an agent enough to decide and invoke correctly. All necessary information is present.

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?

The only parameter, 'domain', is fully documented in the input schema (100% coverage) with an example. The description mentions 'company domain' but adds no new semantics beyond what the schema already provides, so a baseline score of 3 is appropriate.

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 uses a specific verb ('Retrieve') and resource ('overview of a company domain from Revnuvo's observation history'), enumerates the exact fields returned, and names the typical use case. The sibling tool names indicate distinct narrower scopes (technologies, changes, timeline), and this 'overview' aggregates multiple aspects, making it distinguishable.

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 explicitly states when to use it: 'Use it to answer "what do we know about this company?"' This gives clear context for the agent. It doesn't explicitly name alternatives or exclusions, but the overview framing implies when a summary rather than a deep-dive into one aspect is wanted.

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