session_info

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

With no annotations, the description carries the burden and does disclose the key trait: it is non-mutating ("without modifying it"). It stops there, saying nothing about permissions, error behavior, or the freshness of the returned state.

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 covering verb, returned data, and the non-mutating constraint with no wasted words.

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?

An output schema exists, so return values need not be explained, and for a one-param read-only tool the description covers purpose and safety. The missing alternatives guidance is a minor gap, not a blocking one.

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 0%, so the description should compensate. It scopes the identifier to an "artwork session," which gives session_id some meaning, but adds no format or origin detail. The generic param name carries most of the weight.

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?

Specific verb ("Return") plus concrete resource (dimensions, layers, current XCF state) scoped to an artwork session. It clearly reads as an inspection tool distinct from session_list, though it does not name the sibling it differs from.

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?

"without modifying it" implies a read-only inspection use case, but the description never states when to reach for this over session_list, gimp_status, or session_open. No alternatives or preconditions are offered.

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