imessage-mcp

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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the agent knows this is a safe, read-only operation with a closed world. The description adds context about what it queries (expressive_send_style_id) and lists effect types, which helps clarify the scope beyond annotations. However, it doesn't disclose behavioral traits like rate limits, authentication needs, or pagination details (implied by limit parameter). No contradiction with annotations.

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 concise and front-loaded, stating the core purpose in the first phrase. It uses examples efficiently ('slam, loud, gentle, etc.') and adds a clarifying note about querying expressive_send_style_id. Every sentence contributes value, with no redundant information. Minor improvement possible by structuring usage hints.

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 the tool's moderate complexity (analytics with 4 parameters), annotations cover safety (read-only, non-destructive), but no output schema exists. The description provides purpose and scope but lacks details on return format (e.g., what data is returned per effect) or behavioral context like error handling. It's adequate as a starting point but incomplete for full agent understanding without output schema.

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 fully documents all 4 parameters (contact, date_from, date_to, limit) with descriptions and constraints. The description adds no parameter-specific information beyond implying filtering by effect types (e.g., 'slam, loud, etc.'), but this doesn't map directly to schema parameters. Baseline 3 is appropriate as the schema carries the burden.

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: 'iMessage expressive send effects and screen effects analytics' with specific examples like 'slam, loud, gentle, invisible ink, confetti, fireworks, balloons, lasers, etc.' and mentions it 'Queries expressive_send_style_id.' This distinguishes it from siblings like get_reactions or get_read_receipts by focusing on visual/sound effects rather than reactions or read statuses. However, it doesn't explicitly differentiate from all siblings (e.g., message_stats might overlap in analytics).

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 no guidance on when to use this tool versus alternatives. It doesn't mention when to choose it over siblings like get_reactions (for reaction analytics) or message_stats (for general message statistics), nor does it specify prerequisites or exclusions. The agent must infer usage from the purpose alone.

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