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

Beyond the annotations (readOnly=false, openWorld=true, destructive=false), it discloses concrete behavior: the reminder is built from the invoice, emailed to the buyer with a PDF, the seller receives a copy unless send_copy_to_me is false, each call is confirmed by default, and a Cotlet API key with app access is required. This is rich context an agent cannot get from the schema or annotations.

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?

Purpose is front-loaded and most sentences carry useful information, but the confirmation guidance is repeated across two sentences ('By default you confirm each call; you can switch that off' and 'confirm with the user before each call'), which is slightly redundant.

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 carries the full burden and does so: it covers creation source, delivery, recipient, copy behavior, confirmation, and auth requirements. An agent has everything needed to call it correctly.

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 adds real meaning: it maps the type values to their temporal/semantic conditions and clarifies that send_copy_to_me controls the seller copy (default true). This goes beyond the schema's terse field descriptions.

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+resource: emails a Polish payment reminder (Ponaglenie/Monit/Wezwanie) for an unpaid invoice, generating it from the invoice and attaching a PDF. This clearly distinguishes it from siblings like ifirma_send_invoice_email or ifirma_record_payment.

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 selection condition for the three types (reminder before due date, monit after, demand as the formal Wezwanie) and adds a confirmation requirement plus a note that demand is best sent by registered letter. It gives clear when-to-use context per variant, though it does not name a sibling alternative for the same task.

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