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

Adds substantial behavior beyond the readOnly/idempotent annotations: each call creates a viewer, the viewer renews its own retrieval authorization without recapturing, availability follows expiresAt, it requires the original companion connection, and it warns against inferring rendering failure from missing confirmation. This is rich, non-obvious operational context.

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?

Purpose is front-loaded in the first sentence and each subsequent sentence carries distinct operational information (sequencing, viewer semantics, fallback URL, expiry). It is slightly dense at seven sentences but nothing is redundant.

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 no output schema, the description compensates by naming the return artifacts (previewUrl, expiresAt) and the viewer lifecycle. Combined with the annotations, an agent has everything needed to invoke and interpret the call.

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 both UUID parameters are already documented in the schema. The description reinforces 'use the original connection and operationId' but adds no format or syntax detail beyond the schema; 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?

States a specific verb and resource ('Display the original screenshot from a completed screen_screenshot operation') and scopes it to a completed screen_screenshot operation, which cleanly separates it from siblings like remote_status and remote_cancel.

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?

Gives explicit sequencing ('Poll remote_status until completion, then call once'), an exclusion ('Other operation types are rejected'), and a when-not ('do not poll or repeat it unless the user asks to see the screenshot again'). An agent can route to this tool with no inference.

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