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

Annotations already declare readOnlyHint=true and openWorldHint=false, yet the description still adds real context: it reads from an existing 'latest read' rather than triggering a scan, it needs no API key, and it documents failure modes (never-read site, draft, unnamed site return not found). It stops short of saying how fresh that stored read is or what to do when it is stale.

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?

Labeled lines (When / Instead / Inputs / Returns / Fails) front-load the decision-relevant content and no line is filler. Some phrasing is telegraphic — 'fixes and card, a picture to send the person' — which costs a little readability against otherwise tight structure.

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?

For a two-parameter read tool with no output schema, the description covers return shape, both view modes, auth requirements, and failure cases. Nothing an agent needs in order to call it correctly is missing.

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 baseline is 3, but the description earns above it by explaining what `view: agent` actually yields — the whole-site Agent View from the same read, with each AI crawler as robots.txt treats it — which the enum values alone do not convey. `site` adds only the domain-format note already present in the schema.

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 (Gets) and resource (a site's report from its latest read) and enumerates the payload: score, grades, rank, served, fixes with failing pages. The 'Instead' line names three siblings and what each does differently, so an agent can route without opening another 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?

Explicit 'When:' condition ('to tell a person how a site stands') plus an 'Instead:' clause that assigns clickd_brief, clickd_rivals, and clickd_check to their own cases. Both the use case and the exclusions are stated outright.

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