Add Library Symbol Property

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

Annotations already mark this as destructive, and the description adds meaningful behavioral context: the property propagates to all instances, and the tool can update existing properties. It doesn't mention overwrite behavior explicitly but goes beyond mere annotation repetition.

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?

Two sentences, front-loaded with the action and context, no filler. Every word contributes to understanding the tool's purpose and effect.

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 7 parameters and a nested object, the description covers the key contextual point (library-level effect on all instances) and is backed by an output schema. It omits edge cases like missing symbols or library requirements, but remains adequate for typical use.

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 parameters are already documented. The description provides useful examples of property names but does not add deeper semantics for positional or boolean parameters. It meets the baseline for high schema coverage.

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?

The description states a specific verb ('Add or update'), a resource ('custom property on a symbol definition in the lib_symbols section'), and the scope ('available to all instances'). It clearly distinguishes from sibling tools like add_symbol_property by focusing on library-level definitions.

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?

The context is clear: this tool operates on the symbol definition, not on schematic instances. It implies the use case for library-wide property changes. However, it does not explicitly name alternatives or say when not to use it, so it falls short of a 5.

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