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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower. The description adds genuinely useful behavior beyond them: it discloses that return URLs are PDS-native rather than CDN-hosted, and that input accepts a handle or DID.

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?

Front-loaded with the core action and mostly earns its sentences, but contains redundancy ('PDS-native, works for any PDS,not a CDN' repeats the same point, and there's a missing space after the comma) and the CID-reference aside could be tighter.

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?

An output schema exists, so return values need not be explained, yet the description still restates them (CID + getBlob URL). Input requirements, purpose, and the alternative are all covered, leaving nothing an agent needs to call the tool correctly missing.

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%, so the schema already documents repo, limit, and cursor with constraints. The description only echoes 'a handle or DID' for repo and adds no syntax or format detail beyond the structured fields; baseline 3 applies.

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 ('List the blobs ... hosted in an account's repository'), names the underlying lexicon, and clarifies what a blob is (uploaded media/attachments). It also differentiates from the sibling get_blob_info by scope (account-wide listing vs. single-CID lookup).

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 clear context ('Answers what media does this account host?') and points to the alternative ('use this (or get_blob_info) to turn a CID into a fetchable URL'). However, it never states when to prefer get_blob_info over this tool, treating the two as freely interchangeable rather than giving a selecting condition.

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