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

Annotations declare readOnlyHint=false and openWorldHint=true, and the description adds meaningful context beyond them: shared collections expose the saved home to other people, a per-tool confirmation default can be disabled, and the Cotlet API key must have access to this app. This is substantive behavioral disclosure, only slightly weakened by restating the confirmation rule twice.

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 core purpose is front-loaded, but the second sentence ('Saves a listing to your saved homes, and into a collection when collection_id is set') largely restates the first, and the confirmation requirement is repeated. There is avoidable redundancy for a two-parameter tool.

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 two-parameter mutation with no output schema, the description covers the operation, the conditional collection behavior, the external-visibility consequence, the confirmation policy, and auth requirements. Nothing an agent needs to call it correctly is missing.

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 coverage is 100%, so the baseline is 3, but the description goes further by explaining the consequence of collection_id (the home lands in a shared collection visible to others) rather than just naming the parameter. That adds decision-relevant meaning beyond the schema's 'Collection from list_collections.'

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?

States a specific verb and resource ('Save a listing to your saved homes, optionally into one of your collections'), which cleanly separates it from siblings like hemnet_remove_saved_home, hemnet_list_saved_homes, and hemnet_follow_home. An agent can identify the operation without opening the schema.

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?

Explains the conditional path clearly: include collection_id to also file the home into a collection, omit it to save only to saved homes. It also establishes the confirmation expectation before calling. It does not, however, name or compare against sibling alternatives (e.g. follow vs save), so it stops short of explicit when-not guidance.

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