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

Goes meaningfully beyond the annotations (readOnly=false, openWorld=true, destructive=false) by disclosing that calls require per-call confirmation by default, that the action reaches other people, and that a scoped API key is needed. That is real value the annotations do not carry.

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-loads the core action well, but the second sentence largely repeats the first ('master program as their main program or as an add-on, starting on the date you give'), and the confirmation instruction is stated twice. Trimming the duplication would sharpen it.

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 mutating, open-world tool with no output schema and fully documented params, the description covers effect (program appears in each client's app), confirmation behavior, and auth needs. Return values are not explained, but with no output schema and a bulk action that is the main 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%, so the schema already documents program_id, client_ids, start_date, and the main/add_on enum. The description restates the same semantics ('main program or add-on', 'starting on the date you give') without adding format or edge-case detail, so 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 (subscribe) and resource (one or more clients to a master program), plus the two modes (main program vs add-on) and a start date. An agent can immediately tell what the tool does and it is not confusable with any sibling like list_master_programs or assign-style tools.

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?

Offers some operational guidance ('by default you confirm each call; you can switch that off') and a prerequisite (Cotlet API key with access), but never says when to use main vs add_on or when this tool should be chosen over an alternative. Usage is implied rather than delineated.

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