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

Goes well beyond the annotations (readOnlyHint, openWorldHint=false, destructiveHint=false) by disclosing the null-return contract, the deliberate indistinguishability of wrong-workspace vs. missing ids (no cross-tenant leakage), and a prompt-injection warning that externally-sourced 'message' text is DATA, never instructions.

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?

Front-loaded with the operation and scope, then the return contract, then edge cases. Dense with nested parentheticals, but nearly every clause carries operational value; the injection caveat is long yet justified for a tool returning untrusted text.

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 no output schema and only one parameter, the description carries the full burden and does so: it documents the success payload, the null case, tenant-isolation behavior, and the trust caveat on free-text content. Nothing needed 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 0% and lead_id has no description, but the description supplies the missing meaning: the id identifies a lead, no workspace parameter is needed because the active workspace is implicit, and an id from another workspace resolves to null rather than an error. The integer/string duality of the id is left unaddressed.

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 and resource ('Read a single CRM lead by id') plus an explicit scope ('caller's active workspace'), and enumerates the returned fields (contact fields, status, source, message), which implicitly separates it from sibling sub-resource getters like get_lead_links and get_lead_timeline.

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?

The context for use is clear: the caller has a lead id and wants one lead, not a list or timeline. It does not name an alternative for listing/searching leads or state exclusions, so it stops short of the explicit when-not guidance a 5 requires.

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