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

Annotations already declare this a safe read (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description still adds real context: newest-first ordering, studio-defined status values, and an auth prerequisite ('Cotlet API key with access to this app'). Pagination behavior is left to the cursor param rather than explained.

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?

Front-loaded with the core action, but the opening fragment 'Leads with source, status and date added' is largely duplicated by the following sentence's 'filtered by status, source or date added.' That redundant clause costs a point without adding information.

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?

With no output schema, the description usefully hints at returned fields and ordering and covers auth and filtering. It is nearly complete for a simple filtered-list tool; only pagination behavior and default result size are unstated.

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 all four parameters are already documented in the schema, including the studio-defined status semantics. The description restates the status/source/date filter axes without adding syntax or format detail beyond what the schema provides, so the baseline 3 applies.

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 ('Lists prospects in your studio') plus its ordering ('newest first') and its filter axes. It also names the sibling it pairs with (create_prospect), so an agent can distinguish it from zen-planner_list_members or list_classes without opening a 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?

Gives a concrete when-to-use scenario: 'Use it to skip leads that already exist before create_prospect,' which directly ties the read to the write sibling. It lacks explicit when-not guidance or a named alternative for other lead-listing needs, but the context is clear.

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