addMarker

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

Annotations already indicate a non-read-only, non-destructive operation, so the bar is lower. The description adds valuable behavioral context beyond annotations: it discloses the return shape ({ success, data: { entityId }, message? }) and instructs to keep entityId for removeEntity, which helps the agent understand lifecycle management. No contradictions with 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?

The description is two sentences, front-loaded with the core purpose, and includes essential return information without any fluff. Every sentence earns its place, making it highly efficient for an AI agent to parse.

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?

Given the tool's simplicity and the presence of a full input schema and output schema, the description is adequate. It covers the primary action, return value, and a key follow-up (removeEntity). It could optionally mention that this is for map layers, but that is reasonably inferable from the sibling tool names and parameters.

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 fully documents all parameters. The description does not add significant parameter-specific meaning beyond what the schema provides. It reinforces that coordinates are geographic but does not provide additional semantics, so baseline 3 is appropriate.

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 clearly states the action ('Add a point marker') and the resource ('at geographic coordinates'). It distinguishes from sibling tools like addPolygon or addPolyline by explicitly specifying 'point marker.' The return format is also mentioned, leaving no ambiguity about what the tool does.

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 description provides clear context for when to use the tool: adding point markers at coordinates. It does not explicitly mention alternatives or exclusions, but the specificity of 'point marker' implicitly differentiates it from adding other entity types. No misleading guidance is present.

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