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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds value beyond annotations by previewing the return payload (line items, dates, sub_total, tax, total, amount due), which matters since no output schema exists.

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?

A single front-loaded sentence that identifies the resource, its return contents, and the underlying API endpoint with zero waste.

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 enumerates the fields the session returns, which is the main thing an agent needs. It could add a note about empty/invalid session behavior, but it is largely complete for a simple read tool.

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%; the sole session_id parameter is fully documented in the schema, including its origin from checkfront_add_to_booking_session. The description adds no parameter detail beyond this, 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 ('Read') and resource ('booking session') and immediately disambiguates it as the in-progress cart rather than a finalized booking. An agent can distinguish it from checkfront_get_booking and checkfront_create_booking without opening any 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?

Usage is implied rather than stated: the session_id reference to checkfront_add_to_booking_session hints at the cart workflow, but there is no explicit 'use this when...' or exclusion vs checkfront_get_booking, checkfront_end_booking_session, or checkfront_list_bookings. Adequate but leaves routing to inference.

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