cambiar_foto_portada

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

The description's 'Pone' (sets) aligns with readOnlyHint=false (a modifying operation) and no contradiction exists. It adds value beyond annotations by constraining the image source to `buscar_fotos` results or public user images. However, it doesn't disclose what happens to the previous cover photo or any side effects, leaving behavioral depth limited.

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 concise sentence with zero waste. The primary action is front-loaded ('Pone la foto principal de la invitación') followed by the input-source guidance. Every clause earns its place.

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?

Adequate for a simple 2-parameter mutation tool with no output schema and no nested objects. It covers the core action and URL sourcing, but omits error cases, success confirmation, and what happens to the existing photo—gaps that matter for an agent calling a write operation.

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?

With 0% schema description coverage, the description must compensate. It partially does by clarifying `url_foto` (must come from buscar_fotos or be a public image), but `invitacion_id` is left to its self-explanatory name with no added format or purpose detail. The compensation is incomplete given the low 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 and resource: 'Pone la foto principal de la invitación' (sets the main/cover photo of the invitation). This clearly distinguishes it from the sibling `agregar_fotos_galeria`, which adds to a gallery rather than setting a cover. The purpose is unambiguous and specific.

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 gives useful context on the URL source ('Usa una URL de buscar_fotos o una imagen pública del usuario'), which guides the agent on where to fetch input. However, it does not explicitly contrast this tool with `agregar_fotos_galeria` or state when NOT to use it, leaving alternatives implicit.

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