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 needs no restating. The description earns credit by disclosing the response shape — a single lead plus a bounded sample (last 5) of viewed listings and searches plus a total count — which matters since no output schema exists. It stops short of covering error cases, not-found behavior, or whether 'details' is stable across accounts.

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?

One dense sentence that front-loads the payload contents, followed by the endpoint path. The 'GET /leads/lead/{leadID}.' clause is largely redundant with the name and id parameter, but it is short and does not obscure the useful content.

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 2-parameter read with no output schema, the description supplies the essential return-value picture an agent needs to decide whether to call it. Minor gaps remain — no mention of what fields appear in 'details' or of failure behavior for an unknown lead id — but nothing critical 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 description coverage is 100%, so baseline is 3. The description confirms the id-based lookup and the single-record scope, but adds nothing about the optional `fields` projection parameter (which the schema already documents as an rf-style field filter).

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?

Specific verb and resource: fetches one lead by id and enumerates what comes back (details, last 5 viewed listings and searches, total listings viewed). It contrasts implicitly with the plural idx_list_leads, but never names the sibling to make the distinction explicit.

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?

Usage is only implied: you need a single lead and its engagement summary, so you call this. There is no stated when-to-use/when-not, no note on how it differs from idx_list_leads or idx_get_lead_traffic, and no prerequisites such as where the lead id comes from (that hint lives in the schema, not the description).

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