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

Annotations already flag destructiveHint=true, readOnly=false, idempotent=false, openWorld=false. The description adds real value beyond that: it discloses overwrite-on-reuse semantics, account scoping, that it returns what was stored, and that saved watches appear as a one-line notice in later replies. It does not describe permission requirements or limits on the number of saved spaces.

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-loads the save action and the stored-filter set, then handles replace semantics and read-back routing in short clauses. Dense but every sentence carries information; the final sentence about the opening line is a slight digression but still useful.

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?

No output schema exists, and the description covers the return at a high level ('Returns what was stored'). Combined with fully documented parameters and annotations covering the mutation profile, an agent has enough to call and interpret this correctly, though return shape details are thin.

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 every filter parameter is already documented in the schema. The description merely enumerates the filter names (kind, since, new_award, phase, min_amount_usd, matching) without adding format, semantics, or combination behavior beyond the schema. 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+resource: 'Saves a named space from the Whimbrel signal index', and immediately scopes it to the calling account. It also names the sibling check_space_watch as the way to read what is new, so an agent can distinguish save from read without opening either schema.

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?

Explains the salient usage condition — re-saving a name replaces rather than duplicates — and routes the agent to check_space_watch for retrieving new items, and mentions the 'opening line' behavior that surfaces watches automatically. No explicit when-not-to-use guidance, so it falls short of a 5.

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