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

Annotations already declare readOnlyHint/destructiveHint=false, so the bar is lower, yet the description adds real behavioral context: the read is non-advancing, post-submission calls return post_submit_notice and post_submit_links, and the notice must be relayed verbatim with URLs preserved. It still omits failure behavior (expired/invalid handle) and whether reads are idempotent across polls.

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 scope, then output behavior, then input provenance, then exclusions. Four dense sentences with no filler, though the 'do not add an email-delivery caveat' instruction is idiosyncratic and sits awkwardly mid-paragraph.

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, and annotations cover the safety profile. The description still supplies the things structured fields cannot: non-advancing semantics, post-submit handling rules, input provenance, and explicit non-uses.

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% and both params are documented at the source, so the schema does the heavy lifting. The description adds only a mild locational hint ('from the Session section') and otherwise restates that both values must be passed; 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 ('Read the current app cost estimate') plus a crucial scope qualifier ('without advancing it'). It also implicitly distinguishes itself from the mutating siblings (submit_prd, send_action) by naming what it must not be used for.

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?

Explicitly excludes two wrong paths: 'Do not call start_session to recover a session' and 'do not use this tool to approve, edit, or submit.' Combined with 'read without advancing,' an agent knows exactly when this tool applies and which sibling to pick instead.

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