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

readOnlyHint=true already tells the agent this is a safe read, so the description's main addition is the underlying REST endpoint. It does not disclose pagination behavior or result ordering, though the cursor parameter hints at paging. Adequate given annotations carry the safety profile.

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?

Two short sentences, purpose stated first and the API reference appended compactly. No filler, no redundancy with the title.

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 zero-required-parameter read-only list tool with no output schema, this covers what the tool returns at a high level ('definitions/schema') and where it comes from. It stops short of describing the shape of each returned property object, which is the only real remaining gap.

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%, with both limit and starting_after fully documented in the schema, including the next_cursor linkage. The description adds no parameter detail, so the baseline of 3 applies since the 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?

States a specific verb and resource ('List the custom contact-property definitions (schema) for the workspace'), which clearly separates it from bird_list_contacts that returns contact records. It doesn't explicitly name a sibling to contrast with, but the resource is precise enough for an agent to disambiguate.

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?

Usage is only implied: the tool returns schema definitions, so an agent infers it should call this to discover property definitions rather than contact data. There is no explicit when-to-use, when-not-to-use, or named alternative among the many bird_list_* siblings.

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