Download a profile photo

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

Annotations declare readOnlyHint=true and openWorldHint=true. The description adds a concrete behavioral detail: 'Saved under /root/.telegram-agent/downloads.' This clarifies the destination and side-effect of saving a file, going beyond the annotations. It does not cover error cases but adds meaningful 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?

Two short sentences, each serving a purpose. The verb-fronted first sentence states the action, and the second provides the save location. No redundant 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?

For a simple read-only tool with one required parameter, the description covers the core behavior and output location. It omits edge cases like missing profile photos, but given the low complexity and existing annotations, it is reasonably complete.

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 0% and the description does not explain the parameters. 'peer' is only vaguely associated with 'user/chat/channel,' and 'accountId' is completely unaddressed. The description fails to compensate for the lack of schema documentation.

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 tool's action: 'Download the profile photo of a user/chat/channel.' This specifies the verb (download) and resource (profile photo) and differentiates it from siblings like download_media or set_profile_photo.

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 implies the tool is for profile photos but does not explicitly state when to use it over alternatives like download_media. There is no mention of exclusions or preferred contexts, leaving some ambiguity for the agent.

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