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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description earns credit by disclosing the payload shape ('state, category, claim, duplicates and all lead_data fields'), which is the only return-value information available since there is no output schema; it stops short of stating behavior for a missing or inaccessible lead.

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?

Two short sentences with zero filler: the returned content comes first and the endpoint qualifier second. Every clause carries information.

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 one-parameter read tool with annotations covering safety, the definition supplies what the schema cannot: the returned fields, partially compensating for the absent output schema. Only the not-found/error behavior and the source of a valid lead_id are left unaddressed.

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?

Only one parameter exists and schema description coverage is 100%, so the schema alone documents lead_id as a positive integer. The description adds nothing about the identifier's format or origin, which is the baseline expectation when the schema is fully covered.

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 names a single resource ('One lead'), enumerates the returned sub-resources (state, category, claim, duplicates, lead_data), and pins it with the endpoint GET /leads/{id}. This makes it clearly the single-lead fetch as opposed to the list/search siblings, though the verb 'retrieve' is only implied by the endpoint string.

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?

There is no statement of when to use this versus myphoner_find_leads, myphoner_search_leads, or myphoner_list_leads, nor any prerequisite (e.g. that an id must come from one of those tools). The agent must infer the selection rule from the name alone.

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