get_blob

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

With no annotations, the description carries the full burden and does so well: it discloses that bytes are re-hashed and verified against the requested digest, that mismatched blobs are refused with the computed digest reported rather than served, the enumerated error set, and the read-only guarantee. This is behavior an agent could not infer from the schema.

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 read-only marker, then supporting detail. The inline list of returned fields is mildly redundant given an output schema exists, but the prose is tight and every other sentence 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?

For a two-parameter read tool with an output schema, nothing an agent needs is missing: return contents, verification semantics, error taxonomy, and safety profile are all covered. The listing of returned fields is redundant with the output schema but not harmful.

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 already 100%, so the baseline is 3; the description adds real value by explaining that max_bytes produces a too_large result with metadata but no bytes, and it frames content_hash as the digest being verified. It stops short of documenting digest syntax (left to the schema).

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 (Retrieve) and resource (content-addressed blob's bytes by digest) and explicitly positions itself as 'the read-back half of describe_blob', which distinguishes it from its closest sibling. No ambiguity about what is fetched or how it is addressed.

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 'read-back half of describe_blob' framing clearly implies when to use this rather than the metadata-oriented sibling, but it never states an explicit rule (e.g. 'use describe_blob to inspect metadata without downloading bytes') or any exclusions. Clear context, no explicit when-not.

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