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

Annotations only declare readOnlyHint and openWorldHint=false, but the description adds real behavioral context: an empty list is returned when nothing matches, case is ignored where the platform ignores it, and emails are excluded. This goes meaningfully beyond what the annotations convey.

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 purpose is front-loaded as the quoted question, followed by input forms then output behavior. It is a single dense block with no wasted sentences, though the packing of output fields, case rules and the email caveat into one paragraph makes it slightly heavy to scan.

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 restate return values, yet the tool is a simple read lookup whose annotations and schema cover safety and inputs well. The only meaningful gap is any statement of when this should be chosen over the other entry-retrieval siblings.

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 already 100%, so the baseline is 3. The description adds the mutual-exclusivity relationship the schema does not express ('url ... instead of platform and value') and gives concrete value formats (someone or @someone), which helps the agent pick a valid input shape.

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+resource (find entries by handle) and frames it as a reverse lookup, quoting the exact question it answers ('is x.com/someone an official account, and whose?'). This clearly separates it from siblings like get_entries and search_entries, which are not handle-keyed lookups.

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?

Explains the two input ways ('Give a profile's address as url... or platform... and value') and gives an explicit exclusion ('Email addresses are not looked up'). It does not name a competing sibling tool or state when to prefer this over search_entries, so it stops short of full when/when-not routing.

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