get_contact_activity

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

With no annotations provided, the description carries full burden and does well by disclosing key behaviors: it describes the return structure in detail, explains the email vs. id lookup mechanism, and implies read-only operation through 'Get' and investigation context. However, it doesn't mention rate limits, authentication needs, or error handling, leaving some gaps for a tool with no annotation coverage.

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 description is efficiently structured: first sentence states purpose, second provides usage guidelines, third explains parameter semantics, fourth details return values, and fifth gives an example. Each sentence earns its place with no redundant information, making it easy to scan and understand quickly.

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?

Given no annotations and no output schema, the description compensates well by fully explaining the tool's behavior, usage, parameters, and return structure. It covers the complexity of a 4-parameter tool with event grouping and lookup mechanisms, making it complete enough for an agent to use effectively without relying on external documentation.

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 the baseline is 3. The description adds value by explaining the semantic difference between 'email' and 'id' parameters ('email triggers a lookup, id is direct'), which isn't in the schema. It also provides an example with 'limit: 20' to illustrate usage, though it doesn't detail 'since' or default behaviors beyond what the schema already covers.

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 clearly states the tool's purpose: 'Get a contact's recent email-event timeline grouped by event type' with specific event types listed (sent, delivered, opened, etc.). It distinguishes itself from siblings like 'get_contact' or 'get_engagement_summary' by focusing on detailed event-level activity rather than basic contact info or aggregated summaries.

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 description explicitly provides usage guidance: 'When to use: investigate a specific contact's engagement history before sending — e.g. did they bounce on the last campaign, are they frequently opening, when did they last click.' It also clarifies parameter usage: 'Pass email OR id; email triggers a lookup, id is direct,' which helps differentiate from tools requiring both or other identifiers.

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