Add observations

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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds real value beyond them: it discloses the dedup rule (text already present is skipped, which explains *why* the operation is idempotent) and an all-or-nothing failure guarantee ("fails without saving anything"). It does not mention permissions or concurrency behavior.

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 core action is front-loaded in the first line, followed by return behavior, failure semantics, and the sibling alternative — four short sentences with no filler. Every sentence carries distinct information.

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 annotations, a complete input schema, and an output schema (so return structure needn't be spelled out), the description covers the remaining non-obvious aspects: dedup, atomic failure, and the create_entities route. It stops short of only minor details such as permission requirements.

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% and the single parameter is fully documented down to the nested contents/entityName level, so the baseline is 3. The description adds nothing about argument shape or formatting beyond what the schema already says.

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 opens with a specific verb+resource ("Add observations to existing entities") and explicitly scopes it to *existing* entities, immediately separating it from create_entities, which it names. An agent can distinguish this from create_entities, edit_observation, and delete_observations 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?

It states a precondition (all named entities must already exist, or the whole call fails) and routes the agent to create_entities when the target does not yet exist. That is clear context plus one named alternative, though it does not cover when to prefer edit_observation or how to correct an existing observation.

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