streaks

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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, establishing this as a safe, bounded read operation. The description adds valuable behavioral context beyond annotations: it explains the default filtering behavior (excludes contacts you've never replied to), mentions the streak calculation methodology (consecutive-day messaging), and describes the output format (shows longest streak, when it happened, current status). This goes beyond what annotations provide.

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 perfectly concise and well-structured: three sentences that each earn their place. First sentence defines the core concept, second sentence explains what information is returned, third sentence clarifies default behavior. No wasted words, front-loaded with the most important 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 read-only tool with good annotations and full schema coverage, the description provides excellent context about what the tool does and returns. The main gap is the lack of output schema, so the description doesn't specify the exact structure of returned streak data. However, it does describe the semantic content (longest streak, when it happened, current status), which helps compensate. Given the tool's moderate complexity, this is quite complete.

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 schema already fully documents all 4 parameters. The description doesn't add any parameter-specific information beyond what's in the schema descriptions. However, it does provide context about the tool's overall behavior that helps understand parameter usage (like why include_all exists). Baseline 3 is appropriate when schema does the heavy lifting.

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: tracking consecutive-day messaging streaks with contacts, specifically comparing it to Snapchat streaks for iMessage. It distinguishes from siblings by focusing on streak analysis rather than general message retrieval (like get_thread) or contact listing (like list_contacts). The description explicitly mentions showing longest streak, when it happened, and current streak status.

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 provides clear context about when to use this tool (for streak analysis) and includes a default behavior statement (excludes contacts you've never replied to). However, it doesn't explicitly contrast with specific sibling tools like contact_stats or message_stats that might provide overlapping functionality, nor does it mention when NOT to use this tool.

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