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

With no annotations, the description fully discloses behavior: returns newest-first, lists returned fields (id, title, price, category, created_at, canonical URL, stanford_verified), explains pagination via next_cursor, highlights stanford_verified as a trust signal, warns about no personal info, and advises contacting via URL. This is comprehensive.

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 (4 sentences), front-loaded with purpose, and each sentence adds value: purpose, returned fields, trust signal usage, privacy note. No wasted words.

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?

The description covers the tool's return value fields and pagination adequately given no output schema. Minor gaps: no mention of error handling, empty results behavior, or rate limits, but for a search tool this is reasonable.

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 already has descriptions for all 6 parameters (100% coverage), so the baseline is 3. The description adds minimal extra meaning beyond the schema, such as clarifying the cursor is opaque and the default/max limit, but does not significantly enhance parameter understanding.

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: 'Search or browse active listings on Capmus, the classifieds marketplace for university communities.' It uses a specific verb ('search or browse') and resource ('active listings'), and the title distinguishes it from sibling tools like get_listing (single listing) or create_post.

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 implies usage context ('Search or browse active listings') but does not explicitly state when to use this tool versus alternatives like get_listing for a specific listing or list_categories. No exclusions or when-not guidance is provided.

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