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

Annotations already declare readOnly/non-destructive, so the bar is lower; the description still adds real behavior: newest-first ordering, inclusion of caller-personal records, and tenant isolation semantics (wrong-workspace id yields an empty timeline, no cross-tenant leakage). It stops short of describing volume limits or truncation behavior for long timelines.

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 verb and scope, then return contents, then the read-only and tenant-isolation caveats in short clauses. Every sentence carries information; the trailing "Pass 'lead_id'" is slightly redundant but compensates for the undocumented parameter.

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-only tool with no output schema, the description covers what comes back, ordering, and the key failure mode. Missing only edge details such as empty-history behavior for valid ids or result limits.

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% for the single parameter (integer|string, silently required), so the description must supply meaning. Saying 'Pass lead_id' plus the note that an id from another workspace returns an empty timeline tells the agent the id is workspace-scoped and no error is raised. It still doesn't clarify whether both numeric and UUID-style strings are accepted, leaving a small gap.

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: reads a CRM lead's timeline and enumerates what it returns (history events newest-first plus the caller's personal notes/tasks/meeting notes). An agent can tell what it gets without opening the schema. It does not explicitly contrast with near siblings like get_lead or list_lead_activity, which keeps it short of a 5.

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 implied by the framing 'Read a CRM lead's timeline from the caller's active workspace' and the instruction to pass 'lead_id'. There is no explicit when-to-use/when-not-to-use guidance, nor any pointer to alternatives for a related need such as fetching the lead itself or listing raw activity.

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