list_marketplace_items

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds value by emphasizing 'Reads only,' requiring an API key, noting that listings are third-party authored with variable quality, and clarifying that no installation occurs. It complements annotations without contradicting them, providing useful behavioral context beyond the structured metadata.

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 each sentence contributes meaningful information: purpose, usage, constraints, disambiguation, and quality caveat. It is front-loaded with the main action, followed by usage guidance and clarification. There is no fluff or redundancy, making it well-structured and efficient.

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 simple listing tool with no output schema, the description covers the key aspects: it states the read-only nature, authentication requirement, and that results are third-party. It also guides next steps (inspect with get_marketplace_item). It could mention what fields are returned in the list, but given the sibling tool for details and the simplicity, it is sufficiently complete. Slight deduction for not describing the return format, but overall adequate.

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?

The input schema has 100% coverage, meaning all four parameters (page, limit, search, category) already include descriptions in the schema. The description does not add any additional parameter-specific semantics; it only mentions 'search' and 'category' implicitly via the schema. Since the schema already handles parameter documentation, the description adds no extra value, so a baseline score of 3 is appropriate.

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: 'Browse the MisarMail marketplace for ready-made email and automation templates.' It uses a specific verb ('browse') and resource, and explicitly distinguishes itself from sibling tool list_templates by noting they return different things, making it unambiguous.

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 explicit when-to-use guidance: 'Use it to find a starting point instead of authoring from scratch.' It also states that it is browse-only and that nothing is installed or added to the account, and directs users to get_marketplace_item for deeper inspection. It explicitly names the alternative list_templates for account-owned templates, covering both usage and exclusions.

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