Find similar photos

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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds useful behavioral context: the result includes inline thumbnails as an MCP App resource, and warns that some clients (like claude.ai on web) render them only in an expandable panel, with URLs still available. This goes beyond annotations and is valuable for the agent.

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 relatively lengthy but every paragraph serves a purpose: it explains when to use, prerequisites, how users refer to photos (critical for agent understanding), and display behavior. It is front-loaded with the primary usage trigger and then provides necessary details. Slightly verbose but justified by the need to explain the rank vs. photo_id distinction.

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?

The tool has an output schema, so return values are covered there. The description compensates for the complexity of the tool by explaining the relationship between rank and photo_id, which is not obvious from the schema. It also addresses pagination and resource rendering behavior. Given the moderate complexity and presence of output schema, this is adequately complete, though more details on what 'similar' entails could be added.

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%, with both parameters (photo_id and cursor) described in the schema. The description reinforces the use of photo_id (requires it from a prior search) and explains the cursor's role (pass pagination.next_cursor), but adds minimal additional semantics beyond the schema. Baseline 3 is appropriate given full 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 clearly states it finds similar photos based on a photo_id, distinct from sibling search tools by focusing on similarity rather than keywords or image upload. It explicitly ties to user phrases like 'find something similar', making its purpose actionable.

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 explicitly explains when to use the tool ('when the user says...'), specifies the prerequisite (photo_id from a previous search), and details how a person refers to photos (by rank) versus the identifier, which prevents misuse. It also clarifies how to use the cursor for pagination.

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